The motivational effect of detailed job references for volunteers – Evidence from a field experiment on intergenerational cooperation.

Last registered on December 20, 2021


Trial Information

General Information

The motivational effect of detailed job references for volunteers – Evidence from a field experiment on intergenerational cooperation.
Initial registration date
April 07, 2020

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
April 07, 2020, 2:08 PM EDT

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

Last updated
December 20, 2021, 3:37 AM EST

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


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Primary Investigator


Other Primary Investigator(s)

PI Affiliation
Technion Haifa
PI Affiliation
University of Vechta
PI Affiliation
University of Vechta

Additional Trial Information

On going
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
The high importance of career-oriented motivations within the group of young volunteers and recent evidence that volunteering references can improve employment opportunities, suggests that job references for volunteers can motivate young adults to engage in volunteering activities. However, the question of whether job references can also have a motivational effect on the performance and continuation of volunteering remains unanswered. We assume that performance-based job references can help charitable organizations and volunteers to achieve desired volunteer behaviour better than simple job reference without individual performance indication.

In a field experiment in which young volunteers sign up to support elderly citizens as mentor over a longer period of time in using smartphones computers or tablets, we address this research gap and investigate whether and to which extent performance based job references with different underlying performance assessment mechanisms (bonus, repeated betting) can motivate existing volunteers to enlarge their volunteering activities and engage regularly with high intensity for their elderly mentees.
External Link(s)

Registration Citation

Erev, Ido et al. 2021. "The motivational effect of detailed job references for volunteers – Evidence from a field experiment on intergenerational cooperation.." AEA RCT Registry. December 20.
Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Based on literature on young volunteers career motivation, beneficial labor market outcomes for volunteers and non-pecuniary incentives we expect positive motivational effects of job references that display additional information on the individual performance. Mentors receiving detailed job references should provide a higher quantity of telephone calls/Video chats and messages and also more minutes of support compared to volunteers incentivized with a simple job reference. Additionally, we think this effect is reinforced for detailed job references with repeated betting devices as underlying PMA (T2) and young volunteers who are primarily motivated by career concerns.

We measure these interaction parameters for both the incentive period and the post-incentive period.The latter helps us to capture the continuation of the volunteering activities after the end of the project.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Several measures should capture the preparation effort, like number of downloaded supporting material and self-reported preperation time.

As a consequence of the higher regularity and intensity of the assistance provided by young volunteers with detailed job references, we expect several positive effects on their elderly mentees compared to elderly people with control group volunteers:

• Higher decrease in self-reported loneliness
• Higher increase in smartphone use (average minutes per day)
• higher increase in self-reported social integration,
• higher increase in digital competencies,
• higher self-reported decrease in smartphone anxiety
• a higher increase of life-satisfaction

All these measurements are generated by using a pre post comparison.
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We draw our participants from a volunteering project that aims to facilitate intergenerational cooperation between young and reduce feelings of loneliness of old citizens while at the same time increasing the digital expertise of older citizens.
Experimental Design Details
Not available
Randomization Method
Randomization into the three treatment groups is done by a computerized random draw.
Randomization Unit
Individual (volunteers)
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Sample size: planned number of observations
200 tandems are planned
Sample size (or number of clusters) by treatment arms
66 volunteers in each treatment condition
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
German Association for Experimental Economic Research e.V
IRB Approval Date
IRB Approval Number