Alan-Ertac Grit and Growth Mindset Intervention: Study 1

Last registered on October 22, 2018


Trial Information

General Information

Alan-Ertac Grit and Growth Mindset Intervention: Study 1
Initial registration date
October 21, 2018

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
October 22, 2018, 1:05 AM EDT

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



Primary Investigator

European University Institute

Other Primary Investigator(s)

PI Affiliation
Koc University

Additional Trial Information

Start date
End date
Secondary IDs
The growing literature on human capital accumulation has emphasized the importance of socio-emotional skills in explaining individual differences in achievement in various economic and social domains. These skills encompass a broad range of individual character traits, often measured via standardized questionnaires by psychologists and, more recently, via incentivized experimental elicitation techniques by economists. Non-cognitive skills such as patience, self-control and conscientiousness, and preference parameters such as risk attitudes have been shown to be highly predictive of outcomes ranging from educational attainment, occupational and financial success to criminal activity and health outcomes.

In collaboration with the Turkish Ministry of Education, we evaluate a randomized educational program that aims to foster grit. The program involves an intensive teacher training program, supported by a specifically designed curriculum. The curriculum consists of animated videos, mini case studies and classroom activities that highlight i) the plasticity of the human brain against the notion of innately fixed ability, ii) the role of effort in enhancing skills and achieving goals, iii) the importance of a constructive interpretation of failures and therefore perseverance, and iv) the importance of goal setting.

The intervention is randomized across 37 schools in socioeconomically disadvantaged district of Istanbul. We measure the outcomes through a multi-faceted methodology that includes a novel incentivized real effort task, grades and objective test scores. The incentivized real effort task is designed to elicit a number of aspects of grit: challenge seeking, perseverance through setbacks, goal setting and the propensity to engage in effortful behavior to accumulate skill. In addition to experimental choices and outcomes, we administer standardized tests to measure mathematics and verbal (Turkish) skills.

We find that treated students are more likely to exert effort to accumulate task-specific ability, and hence, more likely to succeed. In a follow up 2.5 years after the intervention, we estimate an effect of about 0.2 standard deviations on a standardized math test.
External Link(s)

Registration Citation

Alan, Sule and Seda Ertac. 2018. "Alan-Ertac Grit and Growth Mindset Intervention: Study 1." AEA RCT Registry. October 22.
Former Citation
Alan, Sule and Seda Ertac. 2018. "Alan-Ertac Grit and Growth Mindset Intervention: Study 1." AEA RCT Registry. October 22.
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Experimental Details


The Turkish Ministry of Education encourages schools and teachers to participate in socially useful projects offered by the private sector, NGOs, the government and international organizations. These projects, upon careful examination and endorsement by the Ministry, are made available to interested schools. The Ministry allows up to 5 lecture hours per week for project-related classroom activities, and participation in these projects is at the discretion of teachers. The program we evaluate has been approved as an extracurricular project.

Teachers in the treatment group received full-day training on the delivery of the curriculum. They were advised to use the free hours allowed by the ministry to cover the curriculum and implement the suggested activities. Teachers were encouraged to adopt the ideas put forward in the materials as part of a teaching philosophy, and to implement them by praising students’ effort, perseverant behavior and their positive attitude toward learning, rather than just praising good outcomes. They were also encouraged not to praise a successful student in a way which would imply that the student possesses superior intelligence (in the innate sense of the word), but were rather advised to highlight the role of effort in the student’s success.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
We have two sets of outcomes:
1) Experimental outcomes
2) Achievement outcomes
Primary Outcomes (explanation)
Experimental Outcomes:
1) A novel behavioral task to elicit core features of gritty behaviour:
a. Challenge seeking
b. Perseverance
c. Plan for higher achievement
2) Competitiveness
Achievement Outcomes:
i) Actual success in the behavioral grit task
ii) Objective test scores in math and Turkish (in long-term follow-up)
iii) Teacher-given grades in math and Turkish

Secondary Outcomes

Secondary Outcomes (end points)
self-reported grit (Duckworth grit scale)
self-reported mindset (Dweck mindset scale)
Secondary Outcomes (explanation)
We constructed standardized measures of grit and mindset using item-set survey questions. These constructs are used as intermediate outcomes.

Experimental Design

Experimental Design
This is a two-armed RCT, with each arm targeting a specific non-cognitive skill, patience and grit. We initially sampled 37 schools and collected baseline information. We randomly allocated 15 schools to Initial Treatment (IT), 10 schools to Control-then-Treatment (CT) and the remaining 12 schools to pure control (PC). The program was promised to all participating teachers at some point in two academic years, not to students. Therefore, the design allowed us to conduct long-term tracking of students. We lost 1 CT school after the first follow up of the patience arm (May 2013). In Fall 2013, the IT group received the “grit/mindset” intervention, while the CT group (9 schools) received the “patience” intervention. The CT group never received the grit intervention. Short-term follow-up was done in May 2014, long-term follow up was done in March 2016.
Experimental Design Details
Randomization Method
Teachers in designated schools were called in a random manner. A willing teacher was assigned 40% probability to be in IT, 30% in CT, 30% in PC. Using Stata’s uniform random number generator, we performed the assignment.
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Planned 37 schools. Actual number of clusters=36 schools.
Sample size: planned number of observations
The officially registered number of students in 36 schools is 2575.
Sample size (or number of clusters) by treatment arms
For this evaluation we compare 15 IT schools which were assigned to the program with 21 PC+CT schools which were not.
Official student number for IT= 1443 (15 schools), CT=457, PC=675, Total =2575

Official sample size corresponds to all registered students in participating schools.
Sample size for experimental outcomes is lower because these outcomes were collected from students who were present at the time of the classroom visits.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
We calculate the smallest real effect sizes that we can detect at a 5% significance level with 80% power. We perform the calculation based on 15 treatment and 21 control clusters with approximately 71 students per cluster. Below we display the mean, standard deviation, intracluster correlation coefficient (ICC) and minimum detectable effect (MDE) sizes for our main outcome variables: (i) math and verbal grades given by teachers, (ii) math and verbal test scores as measured using standardized achievement tests, and (iii) experimental choices and outcomes, which comprise students’ choice of the difficult task in round 1, students’ choice of difficult tasks in all five rounds of the first visit, students’ choice of the difficult task for the following week, and students’ success in meeting the target in the second visit. Grades and achievement test scores are standardized to have a mean of zero and a standard deviation of one. When calculating the ICC and MDE for grades and test scores, we take into account that we have baseline information on students’ gender, baseline beliefs and test scores, student ability as measured by the Raven test and class size by first regressing the outcome variable on the baseline characteristics and performing the ICC and MDE calculations using the residuals from that regression. Variable Mean SD ICC MDE In SD/% Math grade 0.00 1.00 0.28* 0.33* 0.33 SD Verbal grade 0.00 1.00 0.16* 0.22* 0.22 SD Math score 0.00 1.00 0.06* 0.23* 0.23 SD Verbal score 0.00 1.00 0.08* 0.23* 0.23 SD Choose Difficult (Round 1) 0.76 0.42 0.05 0.10 13% Choose Difficult (All Rounds 1-5) 0.28 0.45 0.03 0.09 33% Choose Difficult (Second Visit) 0.52 0.50 0.05 0.11 22% Total Payoff 3.29 2.55 0.04 0.57 17% (*) ICC and MDE for grades and test scores calculated using baseline information.
Supporting Documents and Materials

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Institutional Review Boards (IRBs)

IRB Name
Koc University IRB
IRB Approval Date
IRB Approval Number


Post Trial Information

Study Withdrawal

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials