Do women shy away from risky skill games?

Last registered on February 01, 2022


Trial Information

General Information

Do women shy away from risky skill games?
Initial registration date
January 31, 2022

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
February 01, 2022, 4:47 PM EST

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


Primary Investigator

Hanken School of Economics & Helsinki GSE

Other Primary Investigator(s)

PI Affiliation
University of Heidelberg

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
A risky skill game is a game in which skill plays an important role but outcomes are also strongly influenced by random factors. Examples are poker or blackjack but arguably also many economic activities like trading on financial markets. In an online experiment we let subjects choose how often they want to play a slot machine with a stop button. In our chance treatments, the stop button has no influence at all and outcomes depend purely on luck. In our skill treatments, subjects have partial control over outcomes. We check whether women play risky skill games less often than men.
External Link(s)

Registration Citation

Lambrecht, Marco and Jörg Oechssler. 2022. "Do women shy away from risky skill games?." AEA RCT Registry. February 01.
Experimental Details


This project is an attempted self-replication of the main results in Lambrecht and Oechssler (2021, Experiment 1):

"... in High var skill, females play 5.45 rounds on average (CI = [3.95; 6.96]) while males play 14.44 rounds on average (CI = [10.44; 18.44]); t-test, p = .000). Thus, the main result of the paper is
Result 1 In skill gambles with high variance, females play less than half as many rounds as males do."

In this registered experiment we attempt to replicate this result for treatment High var skill with 150 subjects (75 men, 75 women) on Prolific using UK based subjects. The design is identical to Exp. 1.

Given the observed means of rounds played in Exp. 1, we would expect a power of 99%.
STATA command:
power twomeans 5.45 (14.44), n(50 100 150 200 250 300 350 400) sd1(6.62) sd2(16.89) graph
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
rounds played (by gender)
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
bet size, reel stopping success, continuation probability
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
In the main experiment, subjects play repeatedly an online version of a slot machine or one-armed bandit. In each round they receive an endowment and have to decide what share of that endowment they want to bet.The slot machine has two reels with 6 symbols each. The right reel always stops randomly some time after the STOP-button is pressed. The behavior of the left reel depends on the treatment. In our
chance treatments, the left reel also stops randomly. In our skill treatments, subjects are able to stop the left reel by pressing the stop button with a random delay which makes the stopping time slightly less predictable. Nevertheless, given that the symbols always appear in the same order within a round, subjects with a good reaction time can become pretty good at stopping the left reel at the desired symbol. As explained above, one dimension is whether the outcome depends purely on chance or at least partially on skill. The second dimension is low versus high variance, while expected payoffs are held constant.
Experimental Design Details
Randomization Method
implemented in otree code, i.e. done by a computer
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
150 UK citizens
Sample size: planned number of observations
150 UK citizens x 50 rounds
Sample size (or number of clusters) by treatment arms
75 male and 75 female
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Given the data from Lambrecht and Oechssler (2021, Experiment 1) and observed standard deviations of 16.9 and 6.6 for the two groups, we estimate the MDES to be a difference of about 5.9 rounds played, which is roughly 40% of the mean of the baseline (male).

Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number
Analysis Plan

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Post Trial Information

Study Withdrawal

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials