Towards a Cheap Personalization of Political Messaging with Large Language Models?

Last registered on September 27, 2024

Pre-Trial

Trial Information

General Information

Title
Towards a Cheap Personalization of Political Messaging with Large Language Models?
RCT ID
AEARCTR-0014357
Initial registration date
September 16, 2024

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
September 17, 2024, 1:52 PM EDT

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

Last updated
September 27, 2024, 5:57 AM EDT

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

Locations

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Primary Investigator

Affiliation

Other Primary Investigator(s)

Additional Trial Information

Status
In development
Start date
2024-09-16
End date
2025-09-30
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Large languge models (LLMs, like ChatGPT) have been shown to be persuasive in political messaging. Less is known about whether there are personalization gains when using LLMs for political messaging (i.e., when the LLM is asked to tailor a message to a specific demographic group). This project investigates if personalized messages are more effective than unpersonalized messages.
External Link(s)

Registration Citation

Citation
Widmer, Philine. 2024. "Towards a Cheap Personalization of Political Messaging with Large Language Models?." AEA RCT Registry. September 27. https://doi.org/10.1257/rct.14357-1.1
Sponsors & Partners

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Experimental Details

Interventions

Intervention(s)
Intervention Start Date
2024-09-27
Intervention End Date
2024-10-11

Primary Outcomes

Primary Outcomes (end points)
We ask participants for their stance on the policy at hand, for their agreement with the arguments in the message, for the importance they attribute to the topic, how much the message resonates with their political opinion, how much they identify with the message, and how easy or hard the message was to read. Furthermore, we give them the option to generate donations for or against the policy proposed in the message by solving up to ten counting quizzes (the quizzes are voluntary and do not affect the participants' own remuneration).
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
For each message, we make the LLM explain its "reasoning" variable-by-variable. That is, for every variable (e.g., age), the LLM explains why the message should be appealing to somebody who is young (if the message was tailored to a young person). At the end of the survey, participants choose which aspect (if any) they find most or least convincing. Furthermore, we ask participants at the end of the survey whether they think that an artificial intelligence, a human, or both of them authored the post together.
Secondary Outcomes (explanation)
The reasoning question serves to understand whether the LLM's proposed reasons why the message should be convincing to a person with a certain characteristic (e.g., who is young) are agreed upon by participants who actually do have that characteristic. The question on human vs. AI authorship serves to analyze whether personalization affects the perceived authorship.

Experimental Design

Experimental Design
We first randomly assign each participant to one out of six policy topic-stances (three topics with a pro/contra statement each). Afterward, each participant is shown one non-personalized, partly personalized, or fully personalized political message on the assign topic-stance. We then evaluate whether (more) personalized messages are more persuasive.
Experimental Design Details
Not available
Randomization Method
Randomization within survey (by a computer)
Randomization Unit
Individual
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
5000 individuals
Sample size: planned number of observations
5000 individuals
Sample size (or number of clusters) by treatment arms
Treatment is not binary. See the intervention for an explanation. For example, for a participant who identifies as a Democrat or Republican, the message they are shown will match their partisan affiliation with a 50% probability. Similarly, in terms of age, the probability of the message being matched is 33% (considering that the categories are young, middle-aged, old). Since the message is randomly drawn from all possible messages, all of the covariates being matched is rare: 50% (ideology with Liberal/Conservative) * 50% (political partisanship with Democrat/Republican) * 20% (race with Black, White, Hispanic, Asian, Native American) * 50% (gender with male/female) * 33% (financial status with poor, middle-class, upper-class) * 33% (age with young, middle-aged, old) = 0.28%. For categorical variables, note that, in practice, some participants will likely be part of a category not considered in our prompts (e.g., those whose partisanship is "Independent"). Accordingly, the share of those with a match for the categorical variables is, in expectation, slightly lower than what the calculation above suggests. For the continuous variables, we will follow our implementation partner's mapping into categories and evaluate its robustness to other cutoffs.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials

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IRB

Institutional Review Boards (IRBs)

IRB Name
ETH Zurich Ethics Commission
IRB Approval Date
2024-05-24
IRB Approval Number
EK 2024-N-07