Media, ad blockers, and COVID-19

Last registered on February 13, 2023


Trial Information

General Information

Media, ad blockers, and COVID-19
Initial registration date
July 23, 2020

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
July 24, 2020, 10:33 AM EDT

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

Last updated
February 13, 2023, 11:20 AM EST

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


Primary Investigator

Imperial College London

Other Primary Investigator(s)

PI Affiliation
Imperial College London
PI Affiliation
Imperial College London

Additional Trial Information

Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
The COVID-19 outbreak has resulted in an unprecedented media consumption in households, yet this increase in not reflected in additional revenues for newspapers. On the contrary, digital advertising is reported to have decreased. A large problem is related to advertisers using “ad blockers” that effectively prevent their advertisements from be shown next to COVID-related stories. This project will investigate if there are ways to arrest this decline during the crisis. We will conduct an eye-tracking study of a 1000 UK and US participants. The project’s findings would constitute experimental causal evidence regarding whether ads shown next to COVID-related articles harm the advertisers. These findings will help us understand the impact (or lack thereof) of coronavirus on attention to advertising in newsbrands. This may have a dramatic effect on the revenues of one of the communities.
External Link(s)

Registration Citation

Valletti, Tommaso, Andre Veiga and Andre Veiga. 2023. "Media, ad blockers, and COVID-19." AEA RCT Registry. February 13.
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Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
• recall of the ads (spontaneous and prompted ad awareness)
• attitudes to advertising that appears in newsbrands and/or next to Covid content
• willingness to pay/intent to purchase
Primary Outcomes (explanation)
We would primarily analyse the relationship between attention and the questionnaire data. We'd look at recall, looking at the relationship between attention to the ads and subsequent recall of the brand, and any variance between Covid- and non-covid ads; we'd look at brand perceptions and favourability, to see if the context of the ad had any impact on its reception; and we'd cut the questionnaire and attention data by the demographics and psychographics.

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
8 x cells of 125 online representative respondents (a desktop and a mobile cell in each country, each split into a pair of sub cells, n=1000) will be asked to read 12 pages of newsbrand content while having their eyes tracked using a webcam eye tracking software.

The pages will be selected by the researchers, and contain a mixture of ‘hard’ and ‘soft’ news stories, including both COVID- and non-COVID related stories. The sites and pages will be chosen with reference to the sites' daily visitor numbers. The same content and content/advertising combinations will be shown across both mobile and desktop cells. The pages will be served in a random order to remove order effects.

There will be three ad slots on each page
• Desktop 1 x static billboard and 2 static DMPUs (Double Mid Page Units)
• Mobile – 3 MPUs (Mid Page Units)

The number, format and location of ads on each will be held constant to remove the impact of differences in media inventory. All the formats chosen are regularly used in the digital advertising industry and are well understood by publishers and advertisers.

Respondents will be invited to read the pages as they would normally, and then complete a short mental arithmetic exercise, designed to wipe their short term memory and so reduce recency bias

Having done this, they will be asked to answer a questionnaire to assess the primary outcome variables (mentioned above).

A demographic and geographic location questionnaire will have been administered before the test commenced.

Respondents would be fully aware that they are taking part in an eye tracking study and paid for their time. However, we would not reveal to them the objectives of the study before asking them to read the pages and complete the questionnaire.
Experimental Design Details
Randomization Method
Randomization done in office by a computer.
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
8 cells of 125 online representative respondents
Sample size: planned number of observations
1000 respondents
Sample size (or number of clusters) by treatment arms
8 cells of 125 online representative respondents (a desktop and a mobile cell in UK and US , each split into a pair of sub cells, n=1000).
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
Imperial College London - Joint Research Compliance Office
IRB Approval Date
IRB Approval Number


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