AEA RCT Registry

Left-digit Bias in Wage Perceptions and Labor Supply in an Online Labor Market

Last registered on March 01, 2017

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Pre-Trial

Trial Information

General Information

Title

Left-digit Bias in Wage Perceptions and Labor Supply in an Online Labor Market

RCT ID

AEARCTR-0001349

Initial registration date

July 06, 2016

Last updated

March 01, 2017 1:32 PM EST

Location(s)

Country

United States of America

Region

Primary Investigator

Name

Suresh Naidu

Affiliation

Columbia University

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Other Primary Investigator(s)

PI Name

Alan Manning

PI Affiliation

LSE

Contact Investigator

PI Name

Arindrajit Dube

PI Affiliation

UMass Amherst

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Additional Trial Information

Status

In development

Start date

2016-07-06

End date

2017-04-07

Keywords

Electoral, Labor

Additional Keywords

JEL code(s)

Secondary IDs

Abstract

We randomize wages for census image classification task to estimate discontinuous labor supply elasticities at round numbers---in particular at 10 cents, to test for left-digit bias. We also aim to replicate the upward sloping labor supply functions to a given task estimated in Horton et al (2011).

External Link(s)

Registration Citation

Citation

Dube, Arindrajit, Alan Manning and Suresh Naidu. 2017. "Left-digit Bias in Wage Perceptions and Labor Supply in an Online Labor Market." AEA RCT Registry. March 01. https://doi.org/10.1257/rct.1349-2.0.

Former Citation

Dube, Arindrajit et al. 2017. "Left-digit Bias in Wage Perceptions and Labor Supply in an Online Labor Market." AEA RCT Registry. March 01. http://www.socialscienceregistry.org/trials/1349/history/14601.

Sponsors & Partners

Experimental Details

Interventions

Intervention(s)

Intervention Start Date

2016-07-06

Intervention End Date

2016-10-07

Primary Outcomes

Primary Outcomes (end points)

Indicator for accepting MTurk task. Time to complete task. Error rate in tagging.

Primary Outcomes (explanation)

Error rate will be calculated using 2 "known positives" that will be randomly assigned to workers.

Secondary Outcomes

Secondary Outcomes (end points)

Secondary Outcomes (explanation)

Experimental Design

We will post a total of 5,500 unique HITS on MTurk tasks for $0.10 that includes a brief survey and a screening task, where respondents view a digital image of a historical slave census schedule from 1850 or 1860, and answer whether they see markings in the “fugitives” column. Some respondents are offered a choice of completing an additional set of classification tasks for a specific wage.

Extension: we have also run a version of this experiment with a recipe tagging task, at 90, 99, 100, 101, and 110 cents.

Experimental Design Details

We refer to the initial screening part as “stage-1.” Those who complete stage-1 and indicate that the primary reason for participation is "money" or "skills" (as opposed to "fun") are then offered an additional task of completing either 6 or 12 such image classifications (chosen randomly) for a specific (randomized) wage, w, which we refer to as "stage-2." If they accept the stage-2 offer, they are provided either 6 images (task type A) or 12 images (task type B) to classify, and are paid the wage w. These 5,500 HITs will remain posted until completed, or for 3 months, which ever is shorter. Any single individual on mTurk (identified by their MTurk ID) will be allowed to only do one of the HITs. We aim to assess the left-digit bias in wage perceptions experimentally by randomizing the offered wages for HITs on MTurk by randomizing a wage offer for a HIT to vary between $0.05 and $0.15, and assessing whether there is a jump in the acceptance probability between $0.09 and $0.10 as would be predicted by a left-digit bias.

Randomization Method

Randomization done by computer that automatically posts task on Amazon turk.

Randomization Unit

individual MTurk worker.

Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters

5500

400 for extension

Sample size: planned number of observations

5500 400 for extension

Sample size (or number of clusters) by treatment arms

5500

400 for extension