Anchoring and Subjective Belief Distributions

Last registered on March 10, 2026

Pre-Trial

Trial Information

General Information

Title
Anchoring and Subjective Belief Distributions
RCT ID
AEARCTR-0011396
Initial registration date
May 10, 2023

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
May 17, 2023, 2:15 PM EDT

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

Last updated
March 10, 2026, 4:52 AM EDT

Last updated is the most recent time when changes to the trial's registration were published.

Locations

Region

Primary Investigator

Affiliation
University College Dublin

Other Primary Investigator(s)

PI Affiliation
Lund University
PI Affiliation
Lund University
PI Affiliation
Lund University

Additional Trial Information

Status
Completed
Start date
2023-05-11
End date
2024-07-31
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
The purpose of this project is to study how anchors affect estimations of subjective belief distributions (SBDs). Anchoring is a well-known judgment bias in decisions. Although the impact of anchors has been studied extensively on estimations of single-number summary statistics, its impact on higher moments of SBDs is to a large extent unexplored. This makes it valuable to study since SBDs play an important role in economic theory.

A second study using a number input interface is conducted for robustness check.
External Link(s)

Registration Citation

Citation
Holm, Håkan et al. 2026. "Anchoring and Subjective Belief Distributions." AEA RCT Registry. March 10. https://doi.org/10.1257/rct.11396-2.3
Experimental Details

Interventions

Intervention(s)
Low anchor: The subjects are asked if they believe that the a variable is lower or higher than the value of a low anchor
High anchor: The subjects are asked if they believe that the a variable is lower or higher than the value of a high anchor

Mean elicitation The subjects are asked to guess the value of a variable.
Subjective belief distribution (SBD) elicitation: The subjects are asked to input the distribution of a variable using the click-and-drag method (Crosetto and de Haan, 2023)

In a robustness check, we use the number input interface (Crosetto and de Haan, 2023) to elicit distribution.
Intervention (Hidden)
Intervention Start Date
2023-05-11
Intervention End Date
2024-07-31

Primary Outcomes

Primary Outcomes (end points)
-mean of variable
-spread of variable, measured using its variance and coefficient of variation
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
-skew of variable
-match of variable to true value
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We start by giving all subjects information about central concepts in the survey such as the average and the frequency distribution of a set of values. We also let subjects answer a few control questions that are designed to check that the subjects understand the concepts.

The next step is to inform subjects that we have collected information about a given price distribution. It will be a distribution of historical prices for a one-night hotel room in the city of Rome. This distribution was selected since we want the subject to have some idea about the price distribution but not too much information about it.

Subjects are then randomly allocated to one of the following five treatments, where subjects’ beliefs are elicited with monetary incentives.

1. Control elicitation of Distribution (CD). We elicit the SBDs of the hotel room prices using the procedure suggested by Crosetto and de Haan (2023). There is no anchoring in this treatment.

2. Low anchor elicitation of Mean (LM). The subjects are first asked if they believe that the average price is lower or higher than the value of a low anchor. After that subjects are asked to guess the average price of the hotel room.

3. Low anchor elicitation of Distribution (LD). The subjects are first asked if they believe that the average price is lower or higher than the value of a low anchor. After that, we elicit the SBDs of the hotel room prices by the same technique as in CD.

4. High anchor elicitation of Mean (HM). The subjects are first asked if they believe that the average price is lower or higher than the value of a high anchor. After that subjects are asked to guess the average price of the hotel room.

5. High anchor elicitation of Distribution (HD). The subjects are first asked if they believe that the average price is lower or higher than the value of a high anchor. After that, we elicit the SBDs of the hotel room prices by the same technique as in CD.

We then run a 2nd elicitation so that subjects who received the LM and HM will receive CD and subjects who received CD, LD, and HD will be asked to guess the average hotel prices. (Hence, they receive the same treatment as in LM and HM but without any anchor, which will be denoted as M.) In connection with the 2nd elicitation, we will ask how certain the subjects are about their estimations following the elicitation of cognitive uncertainty (CU) by Enke and Graeber (2022). The 2nd round elicitations are of secondary importance and will only be used in the exploratory analysis.

After the treatment, all subjects answer questions about demographics, cognitive reflection, investment behavior, and financial literacy.

In a robustness check, we use the number input interface (Crosetto and de Haan, 2023) to elicit distribution.
Experimental Design Details
Randomization Method
Qualtrics randomizer will be used to allocate subjects into one of the five treatments
Randomization Unit
Individual
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
750 individuals
Sample size: planned number of observations
750 individuals
Sample size (or number of clusters) by treatment arms
150 individuals per treatment
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB

Institutional Review Boards (IRBs)

IRB Name
University College Dublin
IRB Approval Date
2023-03-09
IRB Approval Number
HS-LR-23-37-Samahita
Analysis Plan

Analysis Plan Documents

PAP Study 1

MD5: 9028057646d55551eebba441756a88d1

SHA1: 74e42e19091b4227bc60cde96a2954aab602f581

Uploaded At: May 10, 2023

PAP Study 2

MD5: 6c5e7aec8a005fb591c17746378376e6

SHA1: 4ddaac07969e9dc2157abc55dd6554781d34a3ba

Uploaded At: July 04, 2024

PAP Study 1 AMENDED

MD5: f96eb27dd76148940649bfb3c46de800

SHA1: d3115ede8bcd5b019dce6adf61e95c2d79dfbd93

Uploaded At: July 24, 2025

Post-Trial

Post Trial Information

Study Withdrawal

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Request Information

Intervention

Is the intervention completed?
Yes
Intervention Completion Date
July 08, 2024, 12:00 AM +00:00
Data Collection Complete
Yes
Data Collection Completion Date
July 08, 2024, 12:00 AM +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
1459 participants
Was attrition correlated with treatment status?
No
Final Sample Size: Total Number of Observations
1459 participants
Final Sample Size (or Number of Clusters) by Treatment Arms
Approximately 150 participants per treatment arm (see the published paper for details.)
Data Publication

Data Publication

Is public data available?
Yes
Public Data URL

Program Files

Program Files
Yes
Program Files URL
Reports, Papers & Other Materials

Relevant Paper(s)

Abstract
We investigate how the anchoring effect—a well-established cognitive bias—influences subjective belief distributions. While prior research extensively examines the impact of anchoring and other biases on point estimates, their effect on the underlying distribution and its higher moments remains unexplored. Using two pre-registered online experiments (N = 1467) and two elicitation methods, we find that anchoring impacts not just the mean, but also higher moments of belief distributions. Notably, the traditional anchoring effect in means diminishes when eliciting distributions rather than point estimates. We also find that the elicitation method matters: inattentive participants generate spiky distributions when manually entering numbers for many bins, whereas they generate flat distributions using a click-and-drag interface. These findings show that cognitive biases can extend beyond point estimates, and that the elicitation technique may impact results especially among inattentive participants.
Citation
Håkan J. Holm, Margaret Samahita, Roel van Veldhuizen, Erik Wengström, Anchoring and subjective belief distributions, Journal of Economic Behavior & Organization, Volume 240, 2025, 107304, ISSN 0167-2681, https://doi.org/10.1016/j.jebo.2025.107304. (https://www.sciencedirect.com/science/article/pii/S0167268125004214)

Reports & Other Materials