Knowledge and Freedom III

Last registered on October 07, 2026
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Pre-Trial

Trial Information

General Information

Title
Knowledge and Freedom III
RCT ID
AEARCTR-0019859
Initial registration date
October 05, 2026

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
October 07, 2026, 11:03 AM EDT

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

Locations

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Primary Investigator

Name
Max Grossmann
Affiliation
University of Melbourne
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Other Primary Investigator(s)

Additional Trial Information

Status
In development
Start date
2026-10-05
End date
2027-03-31
Keywords
Behavior, Welfare
Additional Keywords
paternalism, informed choice, information provision, implementation errors, Mill (John Stuart)
JEL code(s)
C91, D91, D81, D82, D83, I31
Secondary IDs
UoM OREI 36925
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
We conduct an experiment to investigate how people make choices for others and under which conditions they intervene in others' choices.
External Link(s)

Registration Citation

Citation
Grossmann, Max. 2026. "Knowledge and Freedom III." AEA RCT Registry. October 07. https://doi.org/10.1257/rct.19859-1.0
Sponsors & Partners

Sponsors

Experimental Details

Interventions

Intervention(s)
Intervention Start Date
2026-10-05
Intervention End Date
2027-03-31

Primary Outcomes

Primary Outcomes (end points)
(1) Intervene: whether the CA assigned an option (Safe Payment or Lottery) instead of keeping the Chooser's button outcome.
(2) Provided: whether the CA chose labeled buttons for the Chooser in the information-provision decision.
(3) ImposeSafe: whether the CA assigned the Safe Payment (rather than the Lottery) in the known-outcome decisions.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
(1) MatchChooser: whether the option assigned in the known-outcome decisions matches the Chooser's Stage 1 preference.
(2) Lean: the option the CA assigns to both members of a pair of Choosers with conflicting Stage 1 preferences (one Safe, one Lottery).

Further measures: CA's own incentivized choice between the two options; personal norm (which option the CA views as most appropriate); incentivized social norm (which option the CA believes most others view as most appropriate); strength of own preference; incentivized beliefs about prior Choosers' choices with labeled and unlabeled buttons; self-reported confidence in the intervention and pair decisions; stated reasons for the intervention decision (open-ended and closed-ended). Analyses beyond those pre-specified in the PAP are exploratory.
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Online experiment with adult participants recruited via Prolific. Participants make incentivized decisions, some of which affect their own payment and some of which affect the payments and choices of other real participants. The study uses between- and within-subject randomization.
Experimental Design Details
Not available
Randomization Method
Randomization is done by a computer program from a pseudorandom number generator.
Randomization Unit
Individual
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
1,284 individuals (Choice Architects). Randomization is at the individual level; there is no clustering. Note: we plan for 1,394 decision-makers in total, but 110 of them are Choosers, who are not the main object of analysis.
Sample size: planned number of observations
1,284 complete Choice Architects (individuals). Each contributes one observation per between-subjects outcome and two known-outcome decisions (one mistake profile, one no-mistake profile).
Sample size (or number of clusters) by treatment arms
Simple (non-blocked) randomization with equal probabilities, so these are expected sizes:
Chooser knowledge: about 642 CAs "Chooser without knowledge" (unlabeled buttons), about 642 CAs "Chooser with knowledge" (labeled buttons).
Narrative (independent of knowledge): about 642 CAs "labels increase Safe Payment uptake", about 642 CAs "labels increase Lottery uptake".
Known-outcome profiles (within-subject, all 1,284 CAs): mistake profile Safe-preferring / Lottery-preferring, about 642 each; no-mistake profiles (unlabeled Safe, unlabeled Lottery, labeled Safe, labeled Lottery), about 321 each.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Benchmark (H2, information provision; binary outcome Provided): with 642 CAs per group, one-sided alpha = 0.05 and 90% power, the MDE is 5 percentage points, from 87% to 92% provision (R power.prop.test). This is about 0.16 SD (SD of the binary outcome about 0.31) and a 5.7% relative increase over 87%. More generally, each of the three primary tests compares two groups of about 642 CAs. Assuming equal group sizes, the MDE at 90% power and one-sided alpha = 0.05 is about 0.163 SD, which for a binary outcome is at most 8.2 percentage points (at a 50% base rate). Not clustered. The H2 MDE increases if revealed leans are unbalanced.
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
University of Melbourne - Office of Research Ethics and Integrity
IRB Approval Date
2026-10-01
IRB Approval Number
36925
Analysis Plan

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