Expert Advice: Understanding Pharmacist Recommendations for branded versus Generic Over-the-Counter medication

Last registered on August 10, 2026
View Trial History

Pre-Trial

Trial Information

General Information

Title
Expert Advice: Understanding Pharmacist Recommendations for branded versus Generic Over-the-Counter medication
RCT ID
AEARCTR-0019351
Initial registration date
August 10, 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
August 10, 2026, 5:17 PM EDT

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

Locations

Country
Canada
Region
Ontario

Primary Investigator

Name
Christi-Anna Durodola
Affiliation
Contact Primary Investigator

Other Primary Investigator(s)

PI Name
Radovan Vadovic
PI Affiliation
Supervisor
Contact Investigator
PI Name
Mehdi Ammi
PI Affiliation
Supervisor
Contact Investigator
PI Name
Vivian Hoffman
PI Affiliation
Collaborator
Contact Investigator

Additional Trial Information

Status
On going
Start date
2025-08-31
End date
2026-08-31
Keywords
Behavior, Health
Additional Keywords
Pharmacists, Generic Drugs, Brand-Name Drugs, Over-the-Counter Medications, Expert Advice, Consumer Decision-Making, Information Asymmetry, Credence Goods, Framing
JEL code(s)
N/a
Secondary IDs
N/a
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
This study examines how pharmacists recommend brand-name versus generic over-the-counter pain medications and whether the way a consumer asks for advice affects the recommendation they receive. Although generic medications contain the same active ingredients as their brand-name equivalents and are often less expensive, consumers may still rely on familiar brand names when choosing over-the-counter medications. Pharmacists are well positioned to help consumers make these choices, but relatively little is known about how they communicate this information during everyday interactions.

The study will take place in community pharmacies in Ottawa, Canada. Researchers will visit pharmacies while posing as ordinary consumers seeking advice about an over-the-counter pain medication. Pharmacies will receive two different types of consumer inquiries on separate visits. One inquiry will be open-ended, allowing the pharmacist to make a recommendation without being presented with specific products. In the other, the consumer will explicitly present a choice between a brand-name and generic version of the same medication and ask the pharmacist which they recommend. The order of the two interactions will vary across pharmacies.

We will compare pharmacists’ recommendations across the two types of interactions. We will also examine the explanations pharmacists provide, including whether they discuss differences or similarities in cost, effectiveness, active ingredients, or product equivalence. The study aims to improve our understanding of how expert advice and the way consumers frame questions can influence decisions between branded and generic medications.
External Link(s)

Registration Citation

Citation
Ammi, Mehdi et al. 2026. "Expert Advice: Understanding Pharmacist Recommendations for branded versus Generic Over-the-Counter medication." AEA RCT Registry. August 10. https://doi.org/10.1257/rct.19351-1.0
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
The study varies how a consumer requests advice from a pharmacist about an over-the-counter pain medication. Participating pharmacy locations are exposed to two standardized consumer inquiry conditions on separate visits. One condition allows the pharmacist to provide an unsolicited product recommendation, while the other makes the choice between alternative versions of the medication more explicit. The order of the two conditions is varied across pharmacy locations. This design allows us to examine whether the framing of a consumer’s request affects the advice provided by pharmacists.
Intervention Start Date
2025-11-14
Intervention End Date
2026-08-31

Primary Outcomes

Primary Outcomes (end points)
Pharmacist recommendation of branded versus generic OTC pain medication. The primary outcome is the type of medication recommended by the pharmacist during the interaction, classified as a generic medication/active ingredient, a brand-name product, both/either, or no clear recommendation.
Primary Outcomes (explanation)
The pharmacist’s recommendation will be coded from the recorded interaction and structured data collection form. The principal outcome for the quantitative analysis will be Generic Recommendation, coded as 1 when the pharmacist recommends a generic OTC medication and 0 when the pharmacist recommends a branded medication. Responses in which both/either is recommended or no clear recommendation is provided will be identified separately and summarized descriptively. The primary analysis will compare recommendation behaviour between the Open-Ended and Brand-versus-Generic conditions using the paired, within-pharmacy study design.

Secondary Outcomes

Secondary Outcomes (end points)
Content and reasoning accompanying the pharmacist’s recommendation. Secondary outcomes include whether the pharmacist mentions brand-generic equivalence, cost, effectiveness, brand familiarity, product availability, the active ingredient/ibuprofen, or product location, as well as any other reasoning offered. We will also examine physical indications of product endorsement and responses to the standardized follow-up question in the Brand-versus-Generic condition.
Secondary Outcomes (explanation)
Secondary outcomes will be constructed from the structured coding of each pharmacist interaction. Separate indicators will identify whether the pharmacist mentions equivalence, cost, effectiveness, brand familiarity, availability, active ingredient/ibuprofen, or product location. Additional information on other reasoning, physical indication of a product, and the response to the follow-up question will also be recorded and analyzed where applicable. These outcomes will be compared across the two consumer inquiry conditions to examine whether question framing affects not only which product pharmacists recommend, but also the information and reasoning they provide.

Experimental Design

Experimental Design
This study uses a naturalistic field experiment in community pharmacies in Ottawa, Canada. Each pharmacy is observed under two different consumer inquiry conditions on separate visits. The order of the conditions varies across pharmacy locations. This paired design allows us to compare how the same pharmacy responds to different ways of framing a request for advice while reducing the influence of stable differences across pharmacy locations. The study focuses on whether consumer framing affects pharmacists’ recommendations between branded and generic over-the-counter pain medications and the information they provide alongside those recommendations.
Experimental Design Details
Not available
Randomization Method
Pharmacies were selected from a master list using stratified random selection based on geographic location and pharmacy type. Selected pharmacies were then randomly assigned to receive either the Open-Ended condition or the Brand-versus-Generic condition on the first visit. Each pharmacy receives the alternate condition on the second visit.
Randomization Unit
Pharmacy location (site). Randomization was conducted at the pharmacy-site level. The randomized element is the order in which each pharmacy receives the two consumer inquiry conditions.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
100 pharmacy locations, with two interactions per pharmacy, for a planned total of approximately 200 pharmacist interactions.
Sample size: planned number of observations
200
Sample size (or number of clusters) by treatment arms
100 BrandvsGeneric
100 Open-ended
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
At a 5% significance level and 80% statistical power, with a planned sample of approximately 100 pharmacy locations observed under both consumer inquiry conditions, the study is designed to detect a minimum difference of approximately 15–20 percentage points in brand-versus-generic recommendation rates between conditions. The exact minimum detectable effect depends on the proportion of pharmacies whose recommendations differ between the two conditions, reflecting the paired within-pharmacy design.
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
Carleton University Research Ethics Board
IRB Approval Date
2025-08-28
IRB Approval Number
124737
Analysis Plan