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Gift Exchange at Work
Last registered on November 23, 2014


Trial Information
General Information
Gift Exchange at Work
Initial registration date
November 23, 2014
Last updated
November 23, 2014 1:20 AM EST
Primary Investigator
Harvard University
Other Primary Investigator(s)
PI Affiliation
University of Chicago
PI Affiliation
University of California, Berkeley
PI Affiliation
University of California, Berkeley
Additional Trial Information
On going
Start date
End date
Secondary IDs
We construct a model of a worker's effort choice that includes altruism, warm glow and reciprocity towards employers, as well as the standard cost of effort and monetary incentive motives. We estimate the model using a natural field experiment with temporary workers. We design the experiment so as to structurally estimate the key parameters, using variation in pay schemes and the returns to the employers. Here, we register the analysis plan, including the fully specified structural model.
External Link(s)
Registration Citation
DellaVigna, Stefano et al. 2014. "Gift Exchange at Work." AEA RCT Registry. November 23. https://doi.org/10.1257/rct.502-1.0.
Former Citation
DellaVigna, Stefano et al. 2014. "Gift Exchange at Work." AEA RCT Registry. November 23. http://www.socialscienceregistry.org/trials/502/history/3133.
Experimental Details
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
The main outcome is the effort exerted by workers in each session, measured as the number of envelopes stuffed (in each 20 minute session).
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
We hire temporary workers for a single day's employment, and within the day vary pay and other features of the work within subject (across different sessions) and between subjects.
Experimental Design Details
Not available
Randomization Method
Randomization of treatment ordering by computer before start of experiment. Assignment to positive, positive in-kind, negative and neutral gift treatments within each daily session happens by stratifying on worker performance in the first half of the day, as described below. In addition, we have variation within subjects in the fixed wage, piece rate and return to employer as they work in 10 different work periods over the course of the day.
Randomization Unit
The experiment uses two types of between-subject variation:
1. First, the order of the experimental sessions is randomized. There are 12 types of sessions, which vary (a) the session order (UP or DOWN), (b) the charity order (CHARITY ORDER 1, 2 or 3) in which one of the charities (B, RN or RIC) corresponds to Charity No 1 in the experimental design, and (c) the match order in the final two sessions (MATCH FIRST or MATCH LAST). This produces 2x3x2=12 treatment session types. The order of the 12 treatments was randomly drawn at the beginning of the study. We plan to hold at least 48 experimental sessions (of which 24 have already been completed as of the time of this posting) and ideally 72 total sessions if we can find enough subjects to recruit. In total, there will be at least 4 full loops through the complete set of 12 treatment sessions, and ideally 6 full loops. In any case, we will aim to run a completed loop though all the 12 sessions constituting one full run. On each day that the experiment is run, either one or sometimes two experimental sessions will be run (depending on how many individuals respond to the posted advertisement and show up).
2. The second randomization is at the individual level, within a given experimental session. Randomization occurs during lunch within an experiment session and is used to determine whether a subject is put into the positive gift, in-kind gift, negative gift, or control (neutral) gift treatment. The total number of envelopes each subject created in the previous sessions is totaled and their rank determined. The highest and lowest rank were put into one treatment, the second highest and second lowest were put into another treatment, and the middle two were put into the third treatment. In the very first experimental session, the highest and lowest rank were randomly placed in the negative gift. Following this, in the second group, the highest and lowest rank were place in the the neutral gift. In the third session, they were placed in the positive gift. This pattern was then repeated. Thus, the randomization was one-time and affected which treatment the first pair of "highest and lowest" workers were assigned to. After that, assignment was deterministic, although of course it depended on worker performance on a given day. The goal was the have ability be balanced over time in the different gift treatments combining over all the sessions, and as similar as possible on average even within a session.
NOTE: This experiment registration, including the full specification of the model and planned structural estimation, was written on 21 Nov 2014. This was after one full phase of data collection, with data on 131 subjects collected and two full rounds of treatment orders (that is, 24 sessions) completed. We plan to gather data on approximately 200 more subjects, making for a total of about 330 workers. But note that exact sample sizes will depend on (unpredictable) show-up of the invited workers. This will require collecting at least another two full rounds of treatment order sessions (T1-T12 twice over, in randomized order) and ideally four more full rounds (pending enough subjects to recruit). Notice that the only difference between the sessions run after Nov. 21, 2014 is the addition of an "in-kind gift" treatment, where workers are provided with an unanticipated gift (a thermos with the logo of the employing charity) in the gift periods, so the subjects are split four-ways in rounds 9-10. This treatment was not included in the first 24 sessions, since we thought of including this treatment after the initial 24 sessions.

In addition, we also utilize within-subject variation:
Each worker works for 10 work sessions in day, during which they face varying incentives. This provides a rich source of within subject variation.
The first of the ten work sessions for each subject is a training session, where the worker is paid to stuff practice envelopes, but the envelopes are discarded and not mailed by the employer (as always, there is no deception in the experiment, and the envelopes are truly discarded as announced to the workers). The fifth session, which is immediately after lunch, is a second training session. The last two sessions -- 9 and 10 -- are always the gift sessions, where workers receive unanticipated positive, negative, in-kind gifts or no gift. The remaining six sessions (other than the two training and two gift sessions) vary in order in one of two ways. Each subject is assigned to either UP or DOWN order, each of which specifies a particular sequence of the work sessions. Importantly, the two orders are reversed or mirror images of each other (excluding the position of the training and gift sessions, which are fixed). Particular pay scheme + employer combinations are thus observed (in different subjects) in two different positions -- once early and once late in the day. By averaging across these two occurrences, we can partially deal with issues of learning and tiredness over the course of the day.
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
Approximately 320 subjects, which might vary slightly due to unpredictable variation in no-shows by the invited potential workers. Of course, workers do not know their treatment status before showing up. Note that while treatment varies within each experimental session (since workers are assigned to different gift treatments for the last two work periods), we can allow the clustered standard errors at the experimental session level in the analysis.
Sample size: planned number of observations
Sample size (or number of clusters) by treatment arms
Approx 90 workers in each of positive gift, control and negative gift treatments, and approximately 50 in the positive in-kind gift session. Approximately 300/12=25 workers in each of the 12 experimental treatments. Total sample size will depend on the number of job seekers who actually show up for each session. We intend to have a total of 48 experimental sessions. The number of experimental sessions might increase if worker show up per session is lower than anticipated.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB Name
Social and Behavioral Sciences Institutional Review Board at the University of Chicago
IRB Approval Date
IRB Approval Number
IRB Name
Social and Behavioral Sciences Institutional Review Board at the University of Chicago
IRB Approval Date
IRB Approval Number
Analysis Plan
Analysis Plan Documents
Analysis Plan - Exp Design, Model, Structural Estimation, Graphical Reduced Form Analysis

MD5: ca03ab4b5d51bba510804190875999f2

SHA1: c4abb6fb738c6e5bad1fd966063a6bc701c844c6

Uploaded At: November 23, 2014