A library in the palm of your hand? Inequalities in Reading Literacy and Educational Attainment.

Last registered on January 15, 2026

Pre-Trial

Trial Information

General Information

Title
A library in the palm of your hand? Inequalities in Reading Literacy and Educational Attainment.
RCT ID
AEARCTR-0008561
Initial registration date
November 12, 2021

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
November 15, 2021, 11:55 AM EST

First published corresponds to when the trial was first made public on the Registry after being reviewed.

Last updated
January 15, 2026, 12:00 PM EST

Last updated is the most recent time when changes to the trial's registration were published.

Locations

Region

Primary Investigator

Affiliation
University of Potsdam

Other Primary Investigator(s)

PI Affiliation
Deutsches Zentrum für Hochschul- und Wissenschaftsforschung (DZHW)
PI Affiliation
IAB
PI Affiliation
University of Potsdam
PI Affiliation
IAB and Universität Bamberg
PI Affiliation
IAB
PI Affiliation
University of Potsdam

Additional Trial Information

Status
Completed
Start date
2021-11-12
End date
2022-12-31
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Multiple studies demonstrate the strong link between parental socio-economic background and children’s academic success. On average, children from households with a lower socio-economic status (SES) have poorer academic achievement, a lower likelihood of going to college, and inferior labor market outcomes throughout their adult life than have children from high-SES households. These adverse outcomes can be partially attributed to lower parental investments, both monetary and non-monetary, as the home learning environment and the resources available to support children’s development vary greatly by parental SES. Children from low-SES families receive less encouragement and smaller incentives to develop cognitive and non-cognitive skills (Cunha et al. 2006; Heckman & Masterov 2007; Law et al. 2018; Kalil et al. 2019).
In Germany, average literacy skills and their distribution differ significantly between children from low and high SES backgrounds (Gambaro et al. 2019). Likely, the Covid-19 pandemic has exacerbated these disparities, as school closures and the resulting disruptions in the educational process have had a particularly negative impact on the academic achievement of those children, whose learning conditions and support options at home were limited compared to their peers.
This project aims to promote out-of-school reading for fifth and sixth grade students from low SES households. Reading literacy is a prerequisite for knowledge acquisition and thus is crucial for the development of cognitive and non-cognitive skills. We draw on survey information of schoolchildren from low-income families – most of them dependent on social welfare – from the study “Corona & Du (CoDu)”. We sampled these families from the Social Security Records of the German Federal Employment Agency, namely the “Integrated Employment Biographies and the Unemployment Benefit II Recipient History.. We examine the extent to which a reading intervention can lead to improvements in reading literacy, academic performance, and higher educational acquisition of children living in low-income households. Therefore, promoting children’s reading literacy might improve their educational pathways as well as their future transition into the labor market, and thus should generate social and economic benefits for the children themselves as well as for society.
External Link(s)

Registration Citation

Citation
Anger, Silke et al. 2026. "A library in the palm of your hand? Inequalities in Reading Literacy and Educational Attainment.." AEA RCT Registry. January 15. https://doi.org/10.1257/rct.8561-2.1
Experimental Details

Interventions

Intervention(s)
Intervention (Hidden)
To sample our study population, we rely on the project “Corona & Du” (CoDu), which sampled families with children aged 10 to 17 from the Social Security Records of the German Federal Employment Agency. In doing so, the survey also sampled from Unemployment Benefit II Recipient History , and, as a result, a significant share of participants come from families dependent on social welfare (Social Code Book). The intervention will be implemented within the group of fifth and sixth grade students who participated in the baseline survey in fall 2020. The intervention concentrates on a disadvantaged sample, as we expect the effects of e-book readers on literacy to be largest among this group. Indeed, young schoolchildren living mainly in households depending on social welfare are an understudied group to which this panel gives us a unique access.

The CoDu study has already collected a large number of educational information and background variables for each participating child during the pandemic. Variables such as reading skills, educational aspirations, and detailed information on parental background– from both the survey and the registers – are of central importance for our RCT on reading competencies and educational attainment. These variables can both serve as controls and might be used for testing randomization. Moreover, we minimize the measurement error related to recall bias, as the necessary pre-treatment information was collected in a timely manner. Another reason for relying on the CoDu sample is methodological. The availability of rich pre-treatment information allows for more efficient randomization. In a nutshell, we can use this data to match students with similar observable pre-treatment characteristics and then conduct stratified randomization. We stratified our sample based on the following variables: (i) an indicator of receiving social assistance, (ii) sex of the child, (iii) school grade of the child, (iv) migration background of the child, and (v) median split of baseline reading literacy.

Furthermore, the geographic spread of CoDu participants and by implication their schools across different federal states reduces concerns about spillover effects from the treatment to the control group compared to a setting, in which students are sampled only from a single school. Finally, given the respondents’ agreement, the CoDu project allows us to link the survey data to the register data of the Federal Employment Agency – the Unemployment Benefit II Recipient History (LHG) and the Integrated Employment Biographies. Thus, we are able to observe the current labor market situation and welfare dependence of the participating families and to analyze labor market outcomes of the children in the future.

To promote disadvantaged children on their educational pathways and on their transition to the labor market, we examine the extent to which a support measure can lead to improvements in school performance and educational attainment of these children. We focus on children in grades five and six, as these are the years also represent a time of critical educational transition in Germany. In most federal states, parents – accompanied by teacher recommendations – decide whether children move to the lower, middle, or academic track after grade four. In grades five and six, this secondary school choice may have to be adjusted according to the child’s achievement.
One important determinant of academic achievement (in a variety of subjects) and thus of later educational success is children’s reading literacy, as several studies have shown (e.g. Kern and Friedman 2008, Hernandez 2011). While studies document the early emergence and persistence of achievement gaps by socioeconomic background (Herbers et al.2012), the joy of reading seems more important for children's educational success than the socioeconomic status of their family (OECD 2002).

In November 2021, the households assigned to the treatment group receive a letter that announces that they have the opportunity to participate in an e-book reader study, where their child in the fifth or sixth grade will receive an e-book reader with access to more than 1.000 books for one year. The letter describes how the study will proceed and asks parents to opt out if the household does not want to participate. We do not replace the households that opted out. About three weeks later, the households receive the e-book readers, which we configure in advance to be in the child protection modus. The e-book readers already contain access to about 1.000 books recommended for the children’s age group.

Part of our intervention is an about monthly mailing of book recommendations. For this purpose, we collaborated with Stiftung Lesen (a charitable foundation aiming to encourage reading) to recommend age appropriate books and to create short videos for a subset of books. With this we aim to reinforce the intensity of the treatment. These book suggestions are also tailored to the children’s “book access”. We host the videos on a secure platform, where only the treated children can access them. We further aim to gain access to individual data capturing the intensity of reading and the types of books read to investigate whether the reading recommendations increase reading intensity.

We plan to conduct at least two separate follow-up waves of the survey with around half a year between each wave. We plan the first follow-up in the second quarter of 2022 and the second follow-up in the fourth quarter of 2022. For both follow-ups, we will send out an invitation to the online survey to the children via their households.
Intervention Start Date
2021-12-10
Intervention End Date
2022-11-30

Primary Outcomes

Primary Outcomes (end points)
Our primary outcomes are:
(i) daily/weekly reading frequencies and average duration
(ii) reading competence
(iii) grades in German and mathematics (contingent of finding a “first stage”)
(iv) educational aspirations (contingent of finding a “first stage”)
Primary Outcomes (explanation)
Participating children are asked to read a text developed or recommended by the Institute for Educational Quality Improvement (IQB) and answer ten questions that test their reading comprehension. We integrate the text into the online survey and we do not impose time limits. The texts used in each wave are comparable in difficulty. Our outcome is the index we construct based on the correct answers.

Secondary Outcomes

Secondary Outcomes (end points)
Our secondary outcomes are:
(i) Non-cognitive skills (e.g. Grit, self-esteem, and social-emotional behavior)
(ii) Leisure time activities
(iii) Occupational aspirations

Longer-run outcomes:
(i) Educational success (degree),
(ii) Labor market success (e.g. School-to-work transition, employment status, and wages derived from registry data)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Individual-level stratified randomization of 1000 students in grades five and six. The study population is derived from a sample of families with children aged 10 to 17 from the Social Security Records of the German Federal Employment Agency.
Experimental Design Details
Randomization Method
Stratified randomization
Randomization Unit
Individuals
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
1000 individuals
Sample size: planned number of observations
1000 individuals
Sample size (or number of clusters) by treatment arms
500 individuals as control units and 500 individuals as treatment units
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials

Documents

Document Name
New Research Projects based on Wave 5
Document Type
proposal
Document Description
In this update, we provide further details about new research projects based on the data collected in the W5 survey.
File
New Research Projects based on Wave 5

MD5:

SHA1:

Uploaded At: January 15, 2026

Document Name
2nd Research Phase
Document Type
proposal
Document Description
In this update, we add details about Wave 5 data collection, the consent question for linking our survey data to administrative data from the Institute for Employment Research (IAB), and new primary and secondary outcome variables.
In addition, we provide an overview of the questions included in our Child Questionnaire (Wave 5) and of our Parental Questionnaire
(Wave 5).
File
2nd Research Phase

MD5:

SHA1:

Uploaded At: January 15, 2026

IRB

Institutional Review Boards (IRBs)

IRB Name
Ethikrat Otto-Friedrich Universität Bamberg
IRB Approval Date
2021-09-24
IRB Approval Number
2021-09/38

Post-Trial

Post Trial Information

Study Withdrawal

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Intervention

Is the intervention completed?
No
Data Collection Complete
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Abstract
Reading comprehension is critical for academic success, yet children from disadvantaged backgrounds often engage in reading less frequently than their more advantaged peers. This study evaluates the impact of a randomized reading intervention targeting 11-12-year-olds from low-income households in Germany. As part of the intervention, children received e-book readers with access to a large digital library of age-appropriate books. The results show a significant increase in reading engagement, leading to improvements
in academic performance. 12 months after the start of the intervention, academic performance improved by 10.3% of a standard deviation, with eects persisting at 9.6% after 30 months. Additionally, the intervention positively impacted the socioemotional well-
being of the children.
Citation
A Library in the Palm of Your Hand? A Randomized Field Experiment with Low-Income Children. IZA DP No. 17322. March 2025.

Reports & Other Materials