Risky Business

The Current State of Teen Privacy in the Android App Marketplace

 

 

The data flows that power today’s digital environment move across generations and cultures, devices and software, businesses and households. Many of the currents that feed into this environment are generated by the mobile app ecosystem, where users of all backgrounds engage with their favorite games, social media, tools, and entertainment sources.

 

Teenagers are major participants in this ecosystem. And like everyone else interacting with today’s connected world, teenagers are faced with questions and tradeoffs when it comes to the use of mobile apps and privacy. 

 

 

In policy discussions about privacy today, however, much of the dialogue focuses on the privacy rights of citizens generally—sometimes through the vehicle of general privacy regulation, and sometimes through protections for specific kinds of data, such as health data or location data. Also common are discussions about prioritizing the privacy interests of young children and whether existing legal frameworks, such as the Children’s Online Privacy Protection Act1 (COPPA), are adequate and sustainable in today’s digital world.

 

 

 

 

 

The Missing Link in Policy Discussions: Teens

The unique privacy interests of teenagers, a significant part of the U.S. population,2 are rarely included in these privacy policy dialogues. This white paper aims to address this shortcoming. 

 

 

 

83%

of U.S. mobile device owners aged 13 to 17 download an app at least once a month3

81%

of teens use social media with 70% saying they use it multiple times a day, up from 34% in 20124

72%

of teens believe that tech companies manipulate users to spend more time on devices5

89%

of teens have their own smartphone, more than doubling since 20126

 

 

 

 

To protect teen privacy interests, some lawmakers are proposing to raise the protected age range under COPPA to include teens7 This year alone, we have seen the PROTECT Kids Act, the Kids PRIVACY Act, and the KIDS Act each applying certain concepts from COPPA to children under the ages of 16 or 17. 

 

The ideas are worthy, but the specifics are lacking. The unique teen audience is strikingly different than COPPA’s current targeted age range of under 13. Defining a website, app, or platform as a “teen space” is much more complex than identifying child-directed content. Teens occupy an intermediate space between childhood and adulthood, which demands a nuanced approach to setting new standards, not merely changing the age limit under COPPA. 

 

Research shows that a teen's drive for greater engagement on digital media platforms exposes them to privacy risks.8 There is a critical need to ensure that companies engaging teens in an online environment collect data in a responsible manner, understand the unique teen audience, and have the tools and support necessary to sustain responsible data collection in an evolving regulatory atmosphere.

 

This study examines the current state of privacy in the Android teen app marketplace and breaks down the privacy risks that teens face with each engagement.

 

 

 

Key Findings

To assess the multiple privacy dimensions of more than 53,000 apps available in the Google Play store, the apps were divided into two categories: apps directed to a general audience, and a subset of those that were directed to teens.

 

The data indicate that Android-based apps likely directed to teens differ substantively from general audience apps where information privacy is concerned.

 

Teen apps have a greater attack surface for privacy risks.

The teen dataset requested more permissions of its users and included more in-app purchase options than apps in the general dataset. And in 9% of apps in the teen dataset we were unable to identify a home country for the app publisher. 

 

 

 

11

median permissions requested per app

6

median "dangerous" permissions requested per app

10

median trackers integrated into each app

 

 

 

Trackers observed most frequently appeared to be controlled by Facebook and Google.

The Android mobile app ecosystem is complex, populated by a variety of publishers that often rely on third-party software to monetize their apps through advertising or in-app purchases.

 

Apps function alongside powerful sensor, storage, and tracking technologies engineered into smartphones. Google, the owner of the Android platform and a powerful advertising network, and Facebook, known for its social media networks, dominate this market through myriad tracking and ad products. Such major players are woven together with innumerable advertising technology companies to create an interlocking mesh of data exchange that funds an enormous swath of internet services.

 

 

 

Many consumers, including teens, engage with their favorite apps every day unaware of the hidden ecosystem that drives them.

 

 

 

Teen users might be targeted based on their in-app purchase spending behavior.

 

The teen dataset included more ad-supported apps than the general dataset.

 

82%

of teen-directed apps

were supported by ads, compared to

51%

of general apps

 

 

 

Games for teens were more likely to have in-app purchases than game apps in the general dataset.

 

General Dataset

4:1

ratio of game apps with in-app purchases to those without

Teen Dataset, almost

13:1

ratio of game apps with in-app purchases to those without

 

 

 

 

 

Why it Matters

Apps targeted to teenage users are more likely to engage in ad serving, include more third-party trackers, ask for more permissions, and offer more in-app purchases.

 

App developers, advertisers, and third-party technology companies routinely focus more heavily on monetizing teenage users, through advertisements and in-app purchases, as compared to general audience users. In addition, the teen dataset included more third-party trackers and requested more permissions to data, including those defined as “dangerous” permissions. While many app developers appear to abide by the Google Play Developer policies about privacy, our study suggests there are important questions about whether they collect or authorize the collection of excessive amounts of data. 

 

And because Google and Facebook own the majority of trackers in teen apps, this report demonstrates how platforms such as these can combine data, collected across a variety of apps, to create a full profile of single users – what they look like, what they sound like, where they go, who their friends and family are, where they work and live, their daily habits and interests, and even the contents of their phone.

 

In a world where teens are restricted from driving, voting, and making other decisions regarding their autonomy, why does the assumption exist that they can properly manage their own data privacy?

 

In today’s landscape, should teens be required to understand and be mindful of the inherent tradeoffs that exist between the data collection and advertising practices in the mobile apps they use and their own personal privacy?

 

Although the proposed laws that expand the scope of COPPA to include some teenagers are well-intentioned, we should not treat teens the same way we treat children, nor should we treat them as fully developed adults.

 

Given our findings and the potential rigidity of future legislative solutions, it is incumbent on industry now to exercise responsibility and show accountability by developing appropriate standards that take into account teens’ habits, preferences, and developmental state. 

 

This study is brought to you by BBB National Programs' TeenAge Privacy Program (TAPP), a community of companies that understand the digital landscape and the complications of standards implementation that will develop the core principles and standards necessary for teen privacy. 

   
   

Methodology

This study analyzes privacy issues surrounding the Android mobile app ecosystem, with a focus on mobile apps directed to teenagers.9 In conducting this study, we aimed to survey the landscape of teen mobile apps for privacy risks and assess how teen data is harvested by the products they use.

 

TAPP’s dataset for this paper is based on a general dataset and a teen dataset.

 

 

General Dataset

To create this dataset, we scraped data from the top 200 apps for each genre10 in the Google Play Store, yielding an initial set of 11,338 apps with accompanying data.11 We then expanded this dataset to include all apps marked by Google Play as similar12 to the initial set of 11,338 apps, yielding a total of 53,686 apps, and scraped app data from the Google Play Store to include the entire expanded dataset13 This scraped data included a list of permissions requested, indicators as to monetization through advertising and in-app purchases, installation counts, links to privacy policies, and in some cases the location of the app publisher.

 

 

Teen Dataset

To create this dataset, we identified popular apps (apps which had been installed 20 million or more times) with characteristics likely directed at teenagers. This process yielded a list of 1,322 apps.

 

To further narrow this sample, we built a multi-factor framework for assessing whether an app was reasonably classified as directed at teens. To construct this framework, we adapted industry standards for marketing to teens, motion picture and software rating guidelines, FTC parameters for assessing the child-directed nature of content for compliance with COPPA, and general knowledge about popular teen products in 2020.14

 

Using this framework as a reference, we manually narrowed our sample to 1,156 teen-directed apps. After identifying these apps, we downloaded the Android application package (APK)15 of each.16  Accounting for minor adjustments and download failures, the final list for the teen dataset consisted of 1,144 apps with accompanying APKs.  

 

For each of these datasets, where possible, we assessed multiple privacy dimensions of each app.

  • The presence and number of permissions each app requested
  • The number of trackers integrated into each app
  • The readability of each app’s description in the app store
  • The presence of each app’s privacy policy
  • Whether each app monetizes through advertising or in-app purchases

 


“Teen Directedness”

In addition, we measured the teen dataset and compared it with the general dataset to confirm that our filtering processes produced a list of teen-focused apps. We looked at three points of comparison:

  1. Does the genre breakdown change between teen and general datasets? We expected, for example, to see fewer utility apps, business apps, etc. in the teen dataset.
  2. Using an appropriate readability scoring formula, is the reading level of the app descriptions on the Google Play Store lower for apps from the teen dataset than for the general dataset? We expect the descriptions of apps targeted at a general audience to score at a higher reading level than the descriptions of apps targeted at teens.
  3. Which words predominate in the descriptions? We expected teen-directed apps to use different words in their descriptions as compared with general apps, and we further expected the most common words to be easily associable with teens, their behavior, or their interests.

 

 

 

Genre of Teen Apps

TAPP’s teen dataset included popular apps known to include teen users, (e.g., TikTok, Instagram, Facebook, Snapchat), gaming, social media, entertainment, messaging, and file sharing. Notably, gaming apps17 consisted of 55.8% of our teen dataset but only 30.1% of our general dataset.

     

    Table 1. Genre Breakdown, Top 10, General Dataset

     

    GENRENumber of apps
    Tools3558
    Education3188
    Health & Fitness2609
    Puzzle Games2306
    Productivity2130
    Lifestyle1936
    Finance1872
    Business1805
    Music & Audio1712
    Entertainment1677


    Table 2. Genre Breakdown, Top 10, Teen Dataset

     

    GENRENumber of apps
    Action Games120
    Casual Games88
    Photography79
    Video Players & Editors70
    Arcade Games64
    Tools59
    Puzzle Games57
    Sports Games56
    Music & Audio55
    Entertainment53


     

    Readability of Teen Apps

    When the app’s descriptions were assessed against the Dale-Chall readability formula,18 which relies on 3000 “familiar words” that are known by 80% of children in the 5th grade, we observed that the average app description for the teen dataset scored approximately 9, while the average app in the general dataset scored 9.59.

     

    Dale-Chall formula

     

    adjusted Score = Raw Score + 3.6365 (if difficult words more than 5%)

     

    ScoreNotes
    4.9 or lowereasily understood by an average 4th-grade student or lower
    5.0–5.9easily understood by an average 5th or 6th-grade student
    6.0–6.9  easily understood by an average 7th or 8th-grade student
    7.0–7.9 easily understood by an average 9th or 10th-grade student
    8.0–8.9easily understood by an average 11th or 12th-grade student
    9.0–9.9easily understood by an average 13th to 15th-grade (college) student

     

     

    Table 3: Reading Level for Dataset App Descriptions

     

    Dataset Dale-Chall Score
    Teen dataset 9.03
    General dataset 9.58
    General dataset minus teen dataset 9.59

     

     

    Word Frequencies, Teen Dataset

    We also analyzed word frequency counts in the summaries and descriptions scraped from the Google Play Store for both the teen dataset and the general dataset (with the apps in the teen dataset removed from the general dataset for this comparison), removing punctuation and connective words (e.g., “and,” “the,” “his,” etc.), and consolidating word forms (e.g., “game” includes “gaming,” “games,” “gamer,” etc.). By comparing the frequently occurring words in each dataset, we were able to determine whether the teen dataset predominantly included words directed to teens, or words indicative of their behavior or interests, relative to the general dataset.

     

    The results confirmed the hypothesis that the teen dataset included words associated with teens and their interests. The following tables illustrate this, showing the most common 30 words in each dataset. While many words common to popular apps (such as “game”) are highly ranked in both datasets, in the teen dataset words such as “challenge,” “music,” and “battle” all rank among the most commonly occurring words but are not found among the most common words in the general dataset. In the general dataset, the predominant words indicate a more utilitarian outlook, such as “learn” and “easy.”

     

    Table 4: 30 Most Common Words, Teen Dataset

     

    Word Count
    Game  3998
    video  3044
    app  2287
    play  2182
    free  1884
    photo  1859
    new  1624
    use  1509
    friend  1455
    feature  1329
    get  1325
    music  1297
    make  1282
    download  1170
    world  1076
    best  1030
    player  1022
    like  962
    share  891
    fun  848
    time  831
    create  816
    mode  813
    one  770
    device  765
    take  765
    support  724
    challenge  690
    effect  687
    battle  644
     

    Table 5: 30 Most Common Words, General Dataset

     

    Word Count
    app  114024
    game  108873
    use  66293
    free  55505
    new  53043
    play  48548
    feature  45705
    get  44045
    make  39100
    time  38804
    help  31556
    find  30483
    video  30392
    support  29451
    best  28568
    device  28241
    one  27332
    like  27273
    world  26529
    learn  26033
    create  25193
    photo  24550
    need  24029
    phone  23059
    download  22376
    easy  22025
    also  21465
    fun  20978
    include  20889
    share  20141
     
     
     

    Monetization: Advertising vs. In-App Purchases

    TAPP further examined the number of apps in each dataset that relied on advertising or in-app purchases for monetization. In the mobile app ecosystem, app publishers frequently rely on advertising in the form of contextual advertising19 or interest-based advertising (IBA, also known as targeted advertising)20 to monetize their products. Additionally, app publishers may integrate the ability to purchase items, features, and upgrades into their apps (in-app purchases or IAP),21 We note that our datasets and our program’s general experience in the mobile app ecosystem show that many mobile apps employ both methods.

     

    • In the teen dataset, almost 83% of apps used advertising to monetize, compared to 51% in the general dataset.
    • In the teen dataset, 78% of apps contained in-app purchases, compared with less than 50% in the general dataset.

     

    When looking at the genres of gaming apps, games for teens were more likely to have in-app purchases. In the teen dataset, the ratio of apps with in-app purchases to those without was almost 13:1, compared to the general dataset's ratio of 4:1.

     

    Table 6: Ad-Supported Apps, General Dataset

     

    Advertising Monetization Number of Apps
    Ad supported 27,335
    Non-ad supported 26,351  

     

    Table 7: Ad-Supported Apps, Teen Dataset

     

    Advertising MonetizationNumber of Apps
    Ad supported948 
    Non-ad supported196 

     

     

    Table 8: In-App Purchase Apps, General Dataset

     

    In-App Purchases MonetizationNumber of Apps
    In-app purchases26,599 
    No in-app purchases27,087 

     

    Table 9: In-App Purchase Apps, Teen Dataset

     

    In-App Purchases MonetizationNumber of Apps
    In-app purchases895 
    No in-app purchases249 

     

     

    Table 10: In-App Purchase Gaming Apps, General Dataset

     

    Gaming AppsNumber of Apps
    In-app purchases12,882 
    No in-app purchases3,254 

     


    Table 11: In-App Purchase Gaming Apps, Teen Dataset

     

    Gaming AppsNumber of Apps
    In-app purchases591 
    No in-app purchases47
     
     

    Identifying Third-Party Data Trackers

    We used Exodus Privacy’s Exodus Core framework22 to identify third-party trackers in downloaded APKs.23 Broadly speaking, a tracker is a type of software intended to collect data about user behavior. A tracker can be a “first-party” tracker, created by an app publisher, or a “third-party” tracker, created by an unaffiliated company and integrated by the publisher.

     

    In mobile apps, trackers commonly collect device identifiers, location data, or other characteristics of a mobile device’s hardware or software to facilitate data collection for IBA, a common means of monetizing mobile apps and websites.24

     

    We disassembled the downloaded APKs from the teen dataset to analyze the “bytecode” of the APKs for the signatures of known trackers and found:

     

    • As seen in Figure 1, the median number of trackers per app was 10.
    • As seen in Table 13, the most common tracker was Google AdMob.
    • Most trackers are owned by Facebook or Google.
    • As seen in Table 14, many of the apps with the highest number of trackers are offered by the Cyprus-based app publisher Outfit7.25
    • As seen in Table 15, Action games have the largest number of aggregate trackers.
    • As seen in Table 16, when gaming apps are taken out of the equation, photography apps have the highest aggregate number of trackers.
    • When we examine genres with 15 or more apps in this dataset, word games have the highest tracker count when calculated by median (17), followed by arcade games (14).
    • When gaming apps are taken out of the equation, when we examined genres with 15 or more apps in this dataset, we found that social media apps have the highest tracker count when calculated by median (11), followed by photography apps (9).

     

       

      Figure 1: Tracker Presence Per App, Teen Dataset

       

       

      Table 13: Top 10 Trackers, Teen Dataset

       

      Tracker Name Number of Apps
      Google AdMob 1086
      Google Firebase Analytics 981
      Facebook Ads 672
      Facebook Login 614
      Facebook Share 594
      Google CrashLytics 580
      Facebook Analytics 579
      Unity3d Ads 567
      Moat (Oracle) 498
      AppLovin 402

        

       

      Table 14: Apps with Highest Number of Trackers, Teen Dataset

       

      App Name Number of Trackers
      Magic Jigsaw Puzzles 47
      My Story: Choose Your Own Path 38
      Perfect 365: One Tap Makeover 37
      Rodeo Stampede: Sky Zoo Safari 37
      Rayman Adventures 36
      My Talking Hank 35
      Text Me: Text Free, Call Free, Second Phone Number 35
      Smurfs’ Village 34
      Swamp Attack 34
      Talking Ben the Dog 34
      International Fashion Stylist: Model Design Studio 33
      My Talking Tom 33
      Talking Tom Cat 33
      AXES.io 33
      Talking Ginger 2 32
      My Talking Tom 2 32
      My Talking Tom Friends 32
      Talking Angela 32
      Talking Tom Candy Run 32
      Talking Tom Gold Run 32
      Talking Tom Jetski2 32
      Amino: Communities and Chats 31
      Talking Tom Hero Dash 31
      My Talking Angela 31
      Checkers 31
      ASKfm-Ask Me Anonymous Questions 30
      Talking Ginger 30
      Talking Tom and Ben News 30
      textPlus: Free Text & Calls 29
      Talking Tom Bubble Shooter 29

       

       

      Table 15. Trackers by Genre, Teen Dataset

       

      App Genre Aggregate Trackers Number of Apps Median Trackers
      Action Games 1,260 120 9
      Casual Games 1,162 88 12
      Arcade Games 881 64 14
      Puzzle Games 779 57 13
      Photography 661 79 9
      Sports 644 56 11
      Entertainment 567 53 9
      Music & Audio 537 55 8
      Video Players & Editors 535 70 7
      Racing Games 518 48 10
       

      Table 16: Trackers by Genre, Games Removed, Teen Dataset

       

      App Genre Aggregate Trackers Number of Apps Median
      Trackers
      Photography 661 79 9
      Entertainment 567 53 9
      Music & Audio 537 55 8
      Video Players & Editors 535 70 7
      Tools 449 59 6
      Social 390 31 11
      Communication 245 37 6
      Personalization 191 21 8
      Health & Fitness 169 22 8
      Shopping 102 11 11
       
       

       

       

      Analyzing App Permissions Requests

      Mobile apps can request permission to access certain device features such as a Global Positioning System (GPS) location, microphone, and/or camera. Permissions requests typically come in the form of a pop-up box that requires the user to either enable or disable the request, while other permissions are enabled automatically in the app, such as permissions for internet access (see Figure 2).26


      Google states that “the purpose of a permission is to protect the privacy of an Android user.”27 Google Play store policies indicate that apps should not ask permission to access something that they do not need to function (e.g., an e-reading app should not need to request a location permission to function).

       

       

      Figure 2: Example – Google App Permission Request

       

      TAPP_3

       

       

      To conduct our analysis of permissions requests, we relied on both public data scraped from the Google Play Store and data that we obtained from each app’s manifest28 as a result of our static analysis. Wherever possible, we relied on the manifest permissions list that we analyzed in each app’s APK. However, to obtain equivalent data when comparing general and teen datasets, we used permissions data scraped from the Google Play Store. This is because the Google Play Store data and the information contained in an app's manifests may differ.

       

      • Based on the data listed in the Google Play Store, apps in the teen dataset requested a median of 11 permissions per app compared to 10 permissions per app in the general dataset.
      • In our static analysis, conducted of the apps in the teen dataset, we found the median number of permissions requested in the teen dataset was 8 (Figure 3).29
      • 282 apps requested 6-7 permissions, the mode of the teen dataset (Figure 3).
      • 5 apps requested more than 50 permissions each, with 2 of those apps requesting over 100 permissions each (Figure 3).
      • Apps from the teen dataset in the “Tools” genre were found to have the largest number of aggregate permissions requests, followed by communication apps (Table 21).
       

      Dangerous Permissions Requests

      The Google Play Store categorizes permissions requests into three categories: normal, signature, and dangerous. Normal permissions requests pose little threat to user privacy, whereas dangerous permissions “involve the user's privacy information or could potentially affect the user's stored data or the operation of other apps.30” For example, accessing a device’s fine location or camera would be considered dangerous permissions requests.

       

      When examining publicly scraped data from the Google Play Store, we found that there was a median of 5 dangerous permissions requested for apps in the general dataset compared to a median of 6 dangerous permissions requested in the teen dataset.

       

      Looking at permissions requests data from the teen dataset’s app manifests, we identified the top 10 dangerous permissions requested across teen-directed apps as well as the top 5 trackers associated with apps requesting those dangerous permissions (Tables 19 & 20).

       

      Though the permissions requests are visible to the user, the trackers themselves are often not. When comparing which trackers appeared with which permissions a specific app requested, adjusting for how many times a tracker appeared overall in the teen dataset, we identified the top 5 trackers associated with each common dangerous permission request.

       

      Echoing the earlier tracker analysis, most trackers identified as frequently co-occurring with dangerous permissions are controlled by Facebook and Google.

       

      Figure 3: Permissions Requested per App, Teen Dataset

       

       

      Table 17: Top 10 Requested Permissions, Teen Dataset

       

      Permission Name FunctionProtection LevelNumber of Apps
      INTERNET Allows applications to open network sockets Normal 1139
      ACCESS_NETWORK_STATE Allows applications to access information about networks Normal 1136
      WAKE_LOCK Allows using PowerManager WakeLocks to keep processor from sleeping or screen from dimming.    Normal 1072
      WRITE_EXTERNAL_STORAGE Allows applications to write to external storage Dangerous 851
      ACCESS_WIFI_STATE Allows applications to access information about Wi-Fi networks Normal 832
      VIBRATE Allows access to the vibrator. Normal 701
      READ_EXTERNAL_STORAGE Allows applications to read from external storage. Any app that declares the WRITE_EXTERNAL_STORAGE permission is implicitly granted this permission. Dangerous 697
      RECEIVE_BOOT_COMPLETED Allows applications to receive the Intent.ACTION_BOOT_COMPLETED that is broadcast after the system finishes booting. Normal 485
      FOREGROUND_SERVICE Allows a regular application to use Service.startForeground. Normal 359
      CAMERA Required to be able to access the camera device. Dangerous 294
       
       

      Table 18: Apps Requesting the Greatest Number of Permissions, Teen Dataset

       

      App Name

      Number of Permissions

      Parallel Space – Multiple accounts & Two face

      102

      Parallel Space Lite – Dual App

      102

      Samsung Smart Switch Mobile

      66

      EasyShare – Ultrafast File Transfer, Free & No Ads

      60

      GO Launcher - 3D parallax Themes & HD Wallpapers

      52

      Truecaller: Caller ID, block fraud & scam calls

      47

      Signal Private Messenger

      47

      Messenger for SMS

      46

      WeChat

      46

      Free phone calls, free texting SMS on free number

      45

      TextNow: Free Texting & Calling App 

      43

      AirDroid: Remote access & File

      43

      UC Browser- Free & Fast Video Downloader, News App 

      41

      C launcher:DIY themes,hide apps,wallpapers,2020

      40

      KakaoTalk: Free Calls & Text

      40

      GO Security－AntiVirus, AppLock, Booster 

      39

      Mi Browser Pro - Video Download, Free, Fast&Secure 

      39

      WhatsApp Messenger

      39

      OK 

      39

      Skype - free IM & video calls 

      38

      APUS Launcher - 3d wallpaper&Themes,Hide apps 

      37

      Safe Security - Antivirus, Booster, Phone Cleaner 

      37

      UC Mini-Download Video Status & Movies 

      37

      Uplive - Live Video Streaming App

      36

      Facebook

      36

      SHAREit - Transfer & Share 

      36

      Mi Remote controller - for TV, STB, AC and more 

      35

      BOTIM - Unblocked Video Call and Voice Cal

      35

      Eyecon: Caller ID, Calls and Phone Contacts 

      34

      AppLock

      34

       

      As seen above, we identified 5 apps requested over 50 permissions each, with 2 of those apps requesting over 100 permissions each. 

       

       

      Table 19: Top 10 Requested Dangerous Permissions, Teen Dataset

       

      Permission Name FunctionNumber of Apps
      WRITE_EXTERNAL_STORAGE Allows app to write to external storage 851
      READ_EXTERNAL_STORAGE Allows app to read from external storage. Any app that declares the WRITE_EXTERNAL_STORAGE permission is implicitly granted this permission. 697
      CAMERA
              		Required to be able to access the camera device. 294
      RECORD_AUDIO Allows app to record audio. (Enables the device microphone) 265
       
      READ_PHONE_STATE Allows read-only access to phone state, including the current cellular network information, the status of any ongoing calls, and a list of any PhoneAccounts registered on the device 281
      ACCESS_COARSE_LOCATION Allows app to access approximate location. 225
      GET_ACCOUNTS Allows access to the list of accounts in the Accounts Service. 216
      ACCESS_FINE_LOCATION
              		Allows app to access precise location 201
      READ_CONTACTS
              		Allows app to read the user's contacts data. 128
      WRITE_CONTACTS Allows app to write the user's contacts data. 50
       
       

      Table 20: Top 5 Trackers Associated with Dangerous Permissions, Teen Dataset

       

      Permission Name Associated Trackers
      WRITE_EXTERNAL_STORAGE Google Crashlytics
      Facebook Login
      Facebook Share
      Facebook Analytics
      Moat
      READ_EXTERNAL_STORAGE Google Crashlytics
      Facebook Login
      Facebook Share
      Facebook Analytics
      Moat
      CAMERA
              		Facebook Share
      Facebook Login
      Google Crashlytics
      Facebook Analytics
      AppsFlyer
      RECORD_AUDIO Facebook Share
      Facebook Login
      Facebook Analytics
      AppsFlyer
      Google Crashlytics 
      ACCESS_COARSE_LOCATION Facebook Share
      Facebook Login
      Facebook Analytics
      Google Grashlytics
      Twitter MoPub
      ACCESS_FINE_LOCATION
              		Facebook Login
      Facebook Share
      Facebook Analytics
      Google Analytics
      Facebook Places
      READ_CONTACTS
              		Google AdMob
      Google Firebase Analytics
      Facebook Ads
      Facebook Login
      Facebook Share
      READ_PHONE_STATE Facebook Login
      Facebook Analytics
      Facebook Share
      Google Crashlytics
      Facebook Places
      GET_ACCOUNTS Facebook Login
      Facebook Share
      Google Crashlytics
      Facebook Analytics
      Facebook Places
      WRITE_CONTACTS Google AdMob
      Google Firebase Analytics
      Facebook Ads
      Facebook Login
      Facebook Share
       
       

      Table 21: Top 10 Genres Requesting Most Permissions, Teen Dataset

       

      1. Tools
      2. Communication
      3. Photography
      4. Video Players & Editors
      5. Action Games
      6. Social
      7. Music & Audio
      8. Casual Games
      9. Entertainment
      10. Personalization

       

       

      Table 22: Top 10 Genres by Number of Permissions Requested, Teen Dataset

       

      App Genre Aggregate
      Permissions      		Number of AppsMedian Permissions
      Tools 1211 59 17
      Communication 1090 37 32
      Photography 925 79 10
      Video Players & Editors 853 70 10
      Action Games 830 120 6
      Social 782 31 23
      Music & Audio 743 55 13
      Casual Games 586 88 6
      Entertainment 584 53 9
      Personalization 494 21 18
       
       

      Table 23: Top 10 per Genre by Number of Permissions Requested, Games Removed, Teen Dataset

       

      App Genre Aggregate
      Permissions      		Number of AppsMedian Permissions
      Tools 1211 59 17
      Communication 1090 37 32
      Photography 925 79 10
      Video Players & Editors 853 70 10
      Social 782 31 23
      Music & Audio 743 55 13
      Entertainment 584 53 9
      Personalization 494 21 18
      Health & Fitness 305 22 11
      Productivity 217 15 15
       
       

      Apps from our teen dataset in the “Tools” genre have the largest number of aggregate permissions, followed by communication apps. When we examine genres with 15 or more apps in our dataset, we find that communications apps request the greatest median number of permissions, followed by social media apps. 

       

       

       

       

      Looking at the Global App Publisher Landscape

      Starting with the information provided in each Play Store profile, TAPP correlated each app in the teen dataset to the country where its developer is based31 to identify the countries32 with the greatest number of apps in the dataset and whose correlating apps contained the most trackers. Notably, approximately 9% of apps in the teen dataset did not provide any clear address information for their developers, which required us to conduct independent research to identify these developers’ home countries.

       

      Using this information, we identified:

       

      • Countries with app publishers with the highest tracker count (Table 25).
      • The countries with apps that requested the most permissions (Table 26).
      • In-app purchase percentages for top app publisher countries (Figure 5).
       

      Table 24: Countries with Greatest Number of Apps, Teen Dataset

       

      Country Number of Apps
      United States 342
      China 119
      United Kingdom 54
      South Korea 46
      Singapore 43
      France 39
      Cyprus 37
      Israel 36
      Russia 30
      India 29
       
       

      Figure 4: Heat Map of Countries with Most Apps, Teen Dataset

       

       

      Below, Table 25 illustrates the median number of trackers per app associated with each country. To provide a more objective look at the overall privacy impact of each country’s app publishers, we set a threshold for each country excluding any with fewer than 30 associated apps. We further provide in Table 26 the countries with the most permissions requested per app from the teen dataset. 

       

       

      Table 25: Countries with Most Trackers per App, Teen Dataset

       

      Country Median Trackers
      Cyprus 28
      Israel 17
      France 13
      United Kingdom 11
      China 10
      United States 9
      Singapore 9
      Russia 7
      South Korea 6
       

      Table 26: Countries with Most Permissions Requested per App, Teen Dataset

       

      Country Median Permissions
      China18
      South Korea15.5
      France 15
      United States14
      Singapore
      		11
      Russia
      		10
      Israel10
      United Kingdom9
      Cyprus9
       
       

      Figure 5: In-App Purchases Percentages, Teen Dataset

       

       

       

      Here, in Figure 5 above, we observe that a high percentage of each country’s app products monetize through in-app purchases.33 We speculate that app developers aim to maximize their monetization through a combination of data collection for advertising and in-app purchases, especially if they offer a product that achieves a high installation count.

       

      Conclusion

      This study demonstrates an unchecked ecosystem of data collection for a uniquely vulnerable audience. Teen data privacy is a complex topic that does not belong in the same conversations as data privacy regulation for children. As the data show, teens are voracious users of digital media platforms, and their quest for greater engagement threatens the safety of their personal data. 

       

      We look forward to more opportunities to continue this research and encourage companies interested in joining the efforts of the TeenAge Privacy Program to reach out and contact us at TAPP@bbbnp.org. 

       

       
       

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      [1] See generally Children's Online Privacy Protection Act of 1998, 15 U.S.C. 6501–6505. See also Federal Trade  Commission, Children's Online Privacy Protection Rule ("COPPA"), https://www.ftc.gov/enforcement/rules/rulemaking-regulatory-reform-proceedings/childrens-online-privacy-protection-rule (last visited Sept. 16, 2020).
       
      [2] See Marketing Charts, US Population Distribution, by Age Group and Gender (July 1, 2019), https://www.marketingcharts.com/charts/us-population-distribution-by-age-and-gender-in-2019/attachment/censusbureau-us-population-distribution-by-age-group-and-gender-july2020, noting individuals between 12-17 year old represent 7.6 percent of the total population.
       
      [3] J. Clement, U.S. mobile device owner monthly app download rate 2018, by age group, Statista, (Dec. 6, 2019), https://www.statista.com/statistics/243794/us-adult-cell-phone-owners-who-have-downloaded-apps-by-age-group/.
       
      [4] Rideout, V., and Robb, M.B., Social Media, Social Life: Teens Reveal Their Experiences, Common Sense Media  (2018), https://www.commonsensemedia.org/sites/default/files/uploads/research/2018-social-media-social-life-executive-summary-web.pdf.

      [5] Id.

       

      [6] Id.

       

      [7] See generally, Congress.gov, H.R.5573 - PROTECT Kids Act, https://www.congress.gov/bill/116th-congress/house-bill/5573?s=1&r=1 (last visited Oct. 22, 2020). Markey.senate.gov, SENATORS MARKEY AND BLUMENTHAL INTRODUCE FIRST-OF-ITS-KIND LEGISLATION TO PROTECT CHILDREN ONLINE FROM HARMFUL CONTENT, DESIGN FEATURES (March 5, 2020),https://www.markey.senate.gov/news/press-releases/senators-markey-and-blumenthal-introduce-first-of-its-kind-legislation-to-protect-children-online-from-harmful-content-designfeatures_#:~:text=and%20Senator%20Richard%20Blumenthal%20(D,and%20Safety%20(KIDS)%20Act.
      &text=%E2%80%9CBig%20Tech%20has%20designed%20their,purchases%2C%E2%80%9D%20said%20Senator
      %20Blumenthal.

       
      [8] Pew Research Center, Teens, Social Media, and Privacy (May 21, 2013), https://www.pewresearch.org/internet/2013/05/21/teens-social-media-and-privacy/.
       
      [9] We note that due to our research methodology it was easier to narrow the focus of this paper to the Android mobile app ecosystem. We do not intend to provide commentary on the privacy practices of Apple and Google in relation to one another. Nothing in this report is intended or should be construed to be an endorsement or critique of a company’s policies or practices.
       
      [10] See generally Google Play Store, Top Charts, https://play.google.com/store/apps/top?hl=en_US (last visited Sept. 9, 2020). Genres can be access by clicking “categories” option. We note that genres include, but are not limited to, the following: 'Dating,' 'Education,' 'Entertainment,” ''Finance,’ etc.
       
      [11] See generally Google-play-scraper, https://github.com/facundoolano/google-play-scraper/ (last visited Sept. 8, 2020).
       
      [12] TAPP notes that a similar app is an app linked on the sidebar of a Google Play Store app page under “similar.”
       
      [13] This figure is the final number of apps for our general dataset after some errors were removed.
       
      [14] The Digital Advertising Accountability Program relied on the following framework to assess the teen-directed nature of apps. (1) The subject matter, including childish pranks, rites of passage, youth romance, fashion, beauty, sports, performing arts, or mental health. (a) Subject matter appealing primarily to children, such as basic spelling or counting, elementary school arithmetic, most coloring books, and low-vocabulary apps, is not considered to be directed at teenagers. (b) Subject matter chiefly of interest to or appropriate only for adults, such as business, finance, gambling, or pornography is not considered to be directed at teenagers (i) Notwithstanding factor (1)(b) of these guidelines, business or utility-oriented apps that provide features of strong interest to teenagers, such as file sharing or video downloading, may be considered as directed to teenagers, even though such apps may appear to be targeted primarily to adults. (2) Visual content, including settings appealing to teenagers such as skate parks, zoos, summer camps, or teen clubs. (a) Visual depictions targeted at teenagers may include depictions of violence, suggestive themes, crude humor, minimal blood, and some strong language. (b) Visual content appealing to young children, such as brightly colored animated creatures, fairy tale settings, or other images or activities associated with young children, is not considered to be directed to teenagers. (c) Visual content chiefly of interest to or appropriate only for adults, such as intense violence, blood and gore, and sexual content is not considered to be directed to teenagers. (3) The use of teenager-oriented characters, activities, or incentives, particularly involving characters under the age of 25. (4) The kind of music or other audio content. (5) Models appearing to be under the age of 25. (6) The presence of celebrities who appeal to teenagers. (7) Language or other characteristics of the app. (8) Whether advertising that promotes or appears on the app is directed to teenagers. (9) Notwithstanding the prior sections of these guidelines, apps which are known to be popular among teenage users may be considered as directed to teenagers, even though such apps may appear to be targeted primarily to other users. We note that this framework was influenced by the Entertainment Software Ratings Board ratings, factors the FTC has established for examining, the child-directed nature of content, https://www.ftc.gov/tips-advice/business-center/guidance/complying-coppa-frequently-asked-questions-0, standards for ratings set by the Motion Picture Association of America, https://www.filmratings.com/downloads/rating_rules.pdf, and the EU’s Responsible Marketing Pact for avoiding the exposure of minors to advertising for alcoholic beverages, https://www.filmratings.com/downloads/rating_rules.pdf. See generally Entertainment Software Ratings Board, Ratings, https://www.esrb.org/ratings/ (last visited Sept. 8, 2020), Federal Trade Commission, Complying with COPPA: Frequently Asked Questions, § D.1., https://www.ftc.gov/tips-advice/business-center/guidance/complying-coppa-frequently-asked-questions (last visited Sept. 8, 2020). FTC v. TinyCo, FTC Matter 132 3209 (Sept. 2014), https://www.ftc.gov/system/files/documents/cases/140916tinycocmpt.pdf. Motion Picture Association, Inc., Classification and Rating Rules (July 24, 2020), https://www.filmratings.com/downloads/rating_rules.pdf. Responsible Marketing Pact, Content of Ads, https://the-rmp.eu/content/ (last visited Sept. 8, 2020).
       
      [15] Android Developers, Application Fundamentals, https://developer.android.com/guide/components/fundamentals(last visited Sept. 29, 2020) (“Android apps can be written using Kotlin, Java, and C++ languages. The Android SDK tools compile your code along with any data and resource files into an APK, an Android package, which is an archive file with an .apk suffix. One APK file contains all the contents of an Android app and is the file that Android-powered devices use to install the app.”).
       
      [16] Gplaycli, https://github.com/matlink/gplaycli (last visited Sept. 8, 2020).
       
      [17] We note that gaming apps constitute multiple genres, e.g. 'Casual,' 'Educational,' 'Music’
       
      [18] Brian Scott, The Dale-Chall 3,000 Word List for Readability Formulas, https://www.readabilityformulas.com/articles/dale-chall-readability-word-list.php (last visited Sept. 9, 2020). See also Readability Formulas, The New Dale-Chall Readability Formula, https://readabilityformulas.com/new-dale-chall-readability-formula.php (last visited Sept. 9 2020).

       

      [19] eMarketer, Mobile Trends 2020: 10 Trends to Monitor As 5G Ramps Up and Privacy Battles Loom, https://on.emarketer.com/rs/867-SLG-901/images/Branch-Mobile%20Trends%202020%20Report%20Sponsorship.pdf (last visited Sept. 16, 2020) (“…[T]here is a resurgence of interest in sophisticated contextual advertising, i.e., using the context of the app or web page to infer the interests of the user instead of gathering historical behavior to gauge those interests.”).
       
      [20] See generally Digital Advertising Alliance, Consumer Assistance, WebChoices and AppChoices,https://youradchoices.com/choices-faq#jr02 (last visited Sept. 16, 2020) (“When a user visits a website or uses an app that works with an advertising network or other online advertising companies, these advertising companies gather information about the user’s browser or device in order to tell when that same user browser or device visits other websites or apps within the same network – even if these content offerings are run by different companies or have different web addresses or brands. Over time, the information gathered about the browser or device may help predict the user’s likely interest in particular categories of ads: for example, users who frequently visit baseball-related websites might receive more ads for the “baseball/sports enthusiast” category, or users who engage with automobile review apps might receive more ads for the particular models of cars that interest them. This inferred interest category is used to provide advertising relevant to the category to a particularly browser or device.”).
       
      [21] Google, Make in-app purchases of Android apps, https://support.google.com/googleplay/answer/1061913?hl=en (last visited Sept. 9, 2020) (“With some apps, you can buy additional content or services within the app. We call these "in-app purchases." Here are some examples of in-app purchases: A sword that gives you more power in a game…A key that unlocks more features of a free app…Virtual currency that can be used for purchases.”). Apple, Buy additional app features with in-app purchases and subscriptions, https://support.apple.com/en-us/HT202023 (last visited Sept. 9, 2020).
       
      [22] See generally Exodus Privacy, Who we are, https://exodus-privacy.eu.org/en/page/who/ (last visited Sept. 8, 2020). See also Exodus-Privacy, https://github.com/Exodus-Privacy/exodus-core (last visited Sept.8, 2020). TAPP notes that the Exodus Core set of frameworks uses “dexdump,” a standard Android platform tool, to disassemble the APK. This tool looks at the app manifest to determine permissions requested, then looks over the bytecode for the signatures of known trackers previously identified by Exodus. Exodus Privacy, Trackers https://reports.exodus-privacy.eu.org/en/trackers/ (Sept 8. 2020). See generally Google Git, Dexdump, https://android.googlesource.com/platform/dalvik/+/09239e3/dexdump (last visited Sept. 8, 2020). Android Developers, App Manifest Overview, https://developer.android.com/guide/topics/manifest/manifest-intro (last visited Sept. 8, 2020). Android Developers, Dalvik bytecode, https://source.android.com/devices/tech/dalvik/dalvik-bytecode (last visited Sept. 8, 2020). See generally Wikipedia, Bytecode, https://en.wikipedia.org/wiki/Bytecode (last visited Sept. 8, 2020) (“Bytecode, also termed portable code or p-code, is a form of instruction set designed for efficient execution by a software interpreter. Unlike human-readable source code, bytecodes are compact numeric codes, constants, and references (normally numeric addresses) that encode the result of compiler parsing and performing semantic analysis of things like type, scope, and nesting depths of program objects.”).
       
      [23] Exodus Privacy, What Exodus Privacy Does, https://exodus-privacy.eu.org/en/page/what/ (last visited Sept. 8, 2020) (“A tracker is a piece of software meant to collect data about you or what you do.”).  Gunes Acar, Online Tracking Technologies and Web Privacy (May 2017),  https://www.esat.kuleuven.be/cosic/publications/thesis-289.pdf (“Android apps and third-parties can access common identifiers present on the smartphone, such as MAC address, Google Advertising ID or IMEI number.”). See generally Interactive Advertising Bureau, Mobile Identity Guide for Marketers (June 2017), https://www.iab.com/wp-content/uploads/2017/06/Mobile-Identity-Guide-for-Marketers-Report.pdf.
       
      [24] See generally Digital Advertising Alliance, DAA Self-Regulatory Principles, https://digitaladvertisingalliance.org/principles  (last visited Sept. 14, 2020). See also OBA Principles Summary at 2, (“The Principles apply to online behavioral advertising, defined as the collection of data online from a particular computer or device regarding Web viewing behaviors over time and across non-affiliate Web sites for the purpose of using such data to predict user preferences or interests to deliver advertising to that computer or device based on the preferences or interests inferred from such Web viewing behaviors.”) See generally Mobile Guidance. TAPP notes that the DAA’s Self Regulatory Principles can be located here: https://digitaladvertisingalliance.org/principles.
       
      [25] See generally Outfit7, Outfit7, https://outfit7.com (last visited Sept. 14, 2020).
       
      [26] Android Developers, Permissions Overview, https://developer.android.com/guide/topics/permissions/overview (last visited Sept. 16, 2020).
       
      [27] Id.  
       
      [28] Android Developers, App Manifest Overview, https://developer.android.com/guide/topics/manifest/manifest-intro (last visited Sept. 16, 2020) (“Every app project must have an AndroidManifest.xml file (with precisely that name) at the root of the project source set. The manifest file describes essential information about your app to the Android build tools, the Android operating system, and Google Play.”).
       
      [29] We note that this discrepancy is likely the result of the way the Google Play Store tracks permissions. Permissions requests listed in old versions of apps may still be listed on the Google Play Store, even if the current version does not request those permissions. Consequently, data from the Google Play Store version will tend to show that an app has a higher permissions requests count, versus the permissions requests count that results from a static analysis of a downloaded APK.
       
      [30] Android Developers, Permissions overview, https://developer.android.com/guide/topics/permissions/overview (last visited Sept. 17, 2020). We do not analyze signature permissions requests as a distinct category in this paper.
       
      [31] Not all of the publicly scraped data for app store pages provided an app publisher location. Of the 1144 apps in the teen dataset, all but 99 could be matched to their developer’s countries based on keyword matches to their provided address. The 99 remaining either had blank addresses or provided so little information that they could not readily be matched to a country. Of those 99, 87 could be matched with countries based on investigating the developers to identify their likely locations. 12 apps remain unmatched.
       
      [32] Chinese Taipei and Hong Kong are included within “Greater China.” See generally Asia-Pacific Economic Cooperation, https://www.apec.org/ (last visited Sept. 9, 2020).
       
      [33] Here, we again used a threshold of countries with at least 30 app products to calculate which countries had a set of apps with the highest percentage of in-app purchases.