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The motivational effect of detailed job references for volunteers – Evidence from a field experiment on intergenerational cooperation.
Last registered on July 04, 2020


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
Last updated
July 04, 2020 1:37 AM EDT
Primary Investigator
Other Primary Investigator(s)
PI Affiliation
University of Vechta
PI Affiliation
University of Vechta
PI Affiliation
Technion Haifa
Additional Trial Information
In development
Start date
End date
Secondary IDs
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 and learning of smartphone applications, we address this research gap and investigate whether and to which extent performance based job references with different underlying performance assessment mechanisms (bonus, single bet, 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. 2020. "The motivational effect of detailed job references for volunteers – Evidence from a field experiment on intergenerational cooperation.." AEA RCT Registry. July 04. https://doi.org/10.1257/rct.5688-1.1.
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 (T3) 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
After registration, the participants complete a pre-survey and download an app to measure their smartphone behaviour on their mobile phone.
In a pre-intervention period (at least ten days for volunteers; for seniors this variable differs from 0-13 days, since the app is only usable for android phones, huge scepticism in this regard and the need to start as fast as possible because seniors became quickly frustrated with the delay of start), the baseline smartphone-use of all participants is measured. At the end of this period the enrolled young volunteers are randomly paired with an elderly person and assigned to one of the four treatment conditions using a pure randomization procedure. Subsequently, they receive the weekly goal, select their preferred type of job reference and answer control questions on the treatments. The senior mentees take part in an additional competency test, which is repeated at the end of the trial to measure the change in smartphone skills. While volunteers in the control group are incentivised with a simple job reference without any information on their individual performance, students in the remaining three conditions receive the opportunity to earn up to 100 “engagement points” on their “detailed” job reference, depending (a) on how often they achieve the weekly goal of providing assistance at least once per week by phoning or video-chatting and (b) the underlying PMA (see above).
The intervention period takes ten weeks. During this period the older mentees work on tasks using their smartphones every week. The younger mentors can support them. Furthermore, we observe weekly target achievement, based on the telephone protocol of participants on these activities.
In a post intervention period of ten weeks, we further observe the smartphone behavior and the exchange between the young and older participants for three weeks, to see whether they continue their volunteering commitment by working together with their mentees on further smartphone tasks.
The study ends with a post-test. Both tandems participate in a post-survey. The elderly persons will also conduct the same competency test, they have already conducted in the pre-intervention period. Most importantly, the young volunteers report the exchange with their mentees by uploading screenshots of the telephone protocol (only phone and video calls with their mentees during the past thirteen weeks, no contents). A crosscheck of the smartphone usage data of both tandem partners allows further statements about the contact intensity and frequency. The participation fee of 15 € will be paid for taking part in both surveys, reporting the exchange with their tandem partners and downloading the app to measure smartphone usage.

The fist tandems started on April 20th. A second wave of tandems started two weeks later. Further waves are planned.
Randomization Method
Randomization into the four 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
32 tandems are planned
Sample size (or number of clusters) by treatment arms
8 volunteers in each treatment condition
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB Name
German Association for Experimental Economic Research e.V
IRB Approval Date
IRB Approval Number
Post Trial Information
Study Withdrawal
Is the intervention completed?
Is data collection complete?
Data Publication
Data Publication
Is public data available?
Program Files
Program Files
Reports, Papers & Other Materials
Relevant Paper(s)