Encouraging switching in the telecommunications market

Last registered on June 03, 2026

View Trial History

Pre-Trial

Trial Information

General Information

Title

Encouraging switching in the telecommunications market

RCT ID

AEARCTR-0018749

Initial registration date

May 25, 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

June 03, 2026, 8:26 AM EDT

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

Locations

Country

United States of America

Region

Unable to disclose country due to anonymity of collaborating firm

Primary Investigator

Name

Jesper Akesson

Affiliation

The Behaviouralist

Contact Primary Investigator

Other Primary Investigator(s)

Additional Trial Information

Status

Completed

Start date

2018-10-01

End date

2019-02-01

Keywords

Behavior

Additional Keywords

Switching, telecommunications

JEL code(s)

Secondary IDs

Prior work

This trial does not extend or rely on any prior RCTs.

Abstract

This study tests whether letters from a telecommunications provider can help landline customers review their calling plan and switch when another plan may suit them better. Many customers remain on old plans for years, even when other options are available from the same provider. We study a large group of landline customers whose existing plans charged a low monthly fee plus prices for many calls.

Customers were randomly assigned either to receive no letter or to receive one of four letters. One letter reminded customers that better deals might be available. A second letter added that changing plan was usually easy. A third letter showed customers what they had been spending each month. A fourth letter described a specific alternative plan and stated its monthly price.

We use company records to measure whether customers contacted the firm, changed plan, adopted the advertised plan, or left the provider. We also use billing and usage data to estimate which customers appeared likely to save money by switching. The study is designed to understand which kinds of information help customers act on better available options, and what continued non-switching implies about the barriers that keep customers on old plans.

External Link(s)

Registration Citation

Citation

Akesson, Jesper. 2026. "Encouraging switching in the telecommunications market." AEA RCT Registry. June 03. https://doi.org/10.1257/rct.18749-1.0

Sponsors & Partners

Experimental Details

Interventions

Intervention(s)

The intervention consisted of mailed letters sent by the telecommunications provider to landline customers. Customers in the control group did not receive an experimental letter. Customers assigned to treatment received one of four letters.

The first letter told customers that better value options might be available and encouraged them to review their current plan. The second letter contained the same message and added that changing plan was usually quick and that customers could normally keep their existing telephone number. The third letter reported the customer’s average monthly spending over the previous year. The fourth letter described a specific flat price calling plan offered by the same provider and stated its monthly price.

The letters were designed to test whether customers respond more to a general reminder, reassurance about the ease of switching, information about what they currently spend, or information about the price of a specific alternative plan.

Intervention (Hidden)

Intervention Start Date

2018-10-01

Intervention End Date

2018-10-02

Primary Outcomes

Primary Outcomes (end points)

The primary outcome is whether the customer made a substantive change to their landline service during the study period. We define this as changing the base calling plan within the provider or leaving the provider.

We also examine related outcomes that help interpret this primary outcome, including whether the customer changed to the specific flat price plan described in one of the letters, whether the customer contacted the provider, and whether the customer changed a calling plan add on.

Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)

Secondary outcomes include whether the customer contacted the provider after receiving the letter, whether the customer adopted the specific flat price calling plan described in the pricing information letter, whether the customer changed a calling plan add on, and whether the customer left the provider.

We also use billing and usage records to construct predicted savings from switching to the advertised flat price plan. These measures allow us to study whether the letters were more effective for customers who appeared likely to save money by switching.

Secondary Outcomes (explanation)

Experimental Design

The study is a natural field experiment conducted with a telecommunications provider. Eligible landline customers were randomly assigned either to a control group that received no experimental letter or to one of several letter treatments sent by the provider.

The letters varied the information given to customers about reviewing or changing their calling plan. Some letters provided a general prompt to review the plan, while others provided more specific information about current spending or an alternative plan. The design allows us to compare the effect of different types of customer communication on plan review and switching behavior.

Outcomes are measured using administrative records from the provider, including customer contact, plan changes, adoption of the advertised plan, and provider exit during the study period.

Experimental Design Details

Randomization Method

Computer randomization

Randomization Unit

Customer

Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters

132,636

Sample size: planned number of observations

132,636

Sample size (or number of clusters) by treatment arms

Control group, 69,778 customers
Notification letter, 24,512 customers
Switching Ease letter, 9,907 customers
Average Spend letter, 11,186 customers
Pricing Information letter, 17,253 customers

Total, 132,636 customers

The design used layered eligibility rules, so the control and Notification groups are shared comparison groups across the treatment arms. Each treatment is compared with the control and Notification customers from the same eligible comparison set. So some observations are "re-used".

Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Supporting Documents and Materials

IRB