Experimental Design Details
Our goal is to compare the responses of recruiters who are told they are in a study to recruiters who are not. We hire real professional recruiters. Each recruiter evaluates a group of 12 job candidates for an opening at a construction firm.
1. Inviting recruiters: To find professional recruiters in all arms of our experiment, we identify a list of independent freelance workers on a platform that we use for communication and payroll. The platform allows us to search prior experience in HR and/or construction using structured fields. Each recruiter's profile includes an hourly rate suggested by the recruiter. We include each qualified recruiter charging less than or equal to $100 per hour in the sample we draw potential subjects from. We will randomly select from this pool of recruiters to invite (more details below), and among those who are invited, we will offer to pay our subjects the hourly rate posted on their profile.
In order to randomly assign these recruiters to a treatment arm and avoid potential imbalances on recruiter characteristics, we will plan to assign treatment via stratified random samples. Each recruiter strata will be determined by the procedure in the attached document ("Stratification Procedure").
We will send out the invitations in batches, and the order in which the batches are invited will be randomized. In each batch, a randomly selected recruiter from each strata will be selected, assigned to a treatment arm, and sent an invitation. The random assignment to treatments will happen according to our proportions outlined below, which places more subjects into the main arms of the experiment. This creates random variation in which batch each recruiter was in (and thus the time and date of their invitation). We will later harness this exogenous variation in the day the invitation was sent as an instrument for the likelihood of accepting our invite in a Heckman-style correction.
In the event that one or many of the accounts we use to invite subjects from is precluded from sending invites by the website then we will stop sending invites from all accounts until the issue is resolved. We will measure how many days since the start of the pause and may include this as a control variable.
Our total goal number of accepted invites is listed in the power calculation section. We plan to send out around 16,000 invitations. We are not sure what the final acceptance rate for our invites will be. We are targeting a total of 1440 acceptances for reasons outlined in our power calculations. We plan to slow hiring of workers as we approach our goal of 1440 finished evaluations, we will do this by only sending materials to a randomly selected percentage of those who accept as we approach our goal. Eventually we will stop hiring workers after we hit our goal due to budgetary constraints, however all invited workers can still be used to understand acceptance rates.
In addition, we plan to randomly assign half of all workers to receive additional followup if they have not responded in a timely fashion. This additional followup will take the form of sending an additional invitation after the initial offer expires (by default 7 days on the platform). This randomized followup can also be used as an instrument in a Heckman-style correction. The randomized other half will not be invited again nor allowed to accept the invitation after it expires in 7 days.
2. Study Design. We plan an RCT with multiple randomizations to help us explore some of the mechanisms for why recruiters may act differently when they are told they are in a study.
Main Effect: Our main experimental manipulation is whether or not the freelance recruiters are made aware they are in a study being run by academics. For this effect, recruiters are randomly assigned either to (A) the ``Framed Field Experiment'' group, in which they are explicitly told they are participating in a research study. Or they are randomly assigned to (B) the ``(Natural) Field Experiment'' group in which they are not. This is visualized as A vs. B in our Pre-Analysis-Plan "Figure: Overview of Design." We also have four additional treatment arms to better understand mechanisms (discussed later in this document and in our pre-analysis plan).
In the “Framed Field Experiment” condition, we explicitly mention the names of our study's authors and academic affiliations in our initial invitation. Recruiters are explicitly told that the company is hypothetical. In addition, recruiters must agree to the terms of an informed consent form. The invitation comes from an account on the platform that discloses the academic affiliation.
In the “Natural Field Experiment” condition, we do not mention the names of our study's authors and academic affiliations. Recruiters are not explicitly told that the company is hypothetical. The invitation comes from an account on the platform that does not disclose the academic affiliation.
Subjects in all conditions are sent the same instructions for the recruiting task. The instructions include information about the position they are hiring for. They also receive 12 one-page job candidate applications and a structured evaluation form to report assessments and decisions about the 12 candidates.
The final differences between the “Framed Field Experiment” and the “(Natural) Field Study” conditions appear on the evaluation form. In the “Framed Field Experiment” condition, recruiters see university branding in the background of the form (versus no branding in the other arm). Also, after they have completed the main task we ask recruiters in the “Framed Field Experiment” a series of questions meant to measure their level of social desirability bias (see Crowne and Marlowe (1960) and Dhar et al. (2022)), and we ask them for their beliefs about what the study is about.
Details of the recruitment wording, the instructions to send to recruiters, example applicant materials, and the structured evaluation form are available in the "Supporting Documents & Materials". We will not tell experimental subjects the goals of this experiment. The attached pre-analysis plan specifies how we will study the results of this randomization.
We measure if there is differential acceptance of our invites by recruiters in treatment A vs B. Additionally, we measure if there are disparities in recruiter-reported outcomes (e.g. interview, salary offer) for applicants by different attributes of the candidates: race, criminal record and gender for recruiters who know they are in a study (B) vs those that do not (A).
C. Mechanisms
There are several reasons that recruiters may respond differently in academic studies versus natural settings. To help test these mechanisms, we have designed additional treatments that recruiters may be randomized into.
One reason that recruiters may act differently in academic studies is there is no opportunity to be hired again. In Condition (C), a version of a “natural field experiment”, we do not disclose that the task is for a research project. However, we explicitly tell the recruiter the task is a one-time job. Our aim is to lower the stakes, making the stakes more equal to those in the academic study branch of the experiment.
In Condition (D), a version of a “natural field experiment”, recruiters are not contacted by an academic. However, the contact states that the firm has an academic research partner who will get the data to analyze. This allows us to test if being observed by academics drives participation and inequality in how the applicants are treated.
In Condition (E), a version of a “framed field experiment”, the recruiters are told they are an experiment. However, we offer the subjects confidentiality by reminding subjects their responses are confidential and prompting them to enter a six-digit code to be associated with their answers. This condition attempts to vary how much social desirability may drive our results. We tell them about this confidentiality when we invite them to the study.
Finally, in Condition (F), a version of a “framed field experiment”, the recruiters workers are told they are an experiment. However, we offer to leave a review on the platform that mentions the recruiter being reviewed in their capacity as a human resources professional. We tell them about this type of review when we invite them to the study. This tests whether the fact that study participants may not get helpful reviews for future work on the platform is driving any differences in responses.