Use of Airtime Incentives to Improve Short Message Service Surveys in Colombia and Tanzania

Study Overview
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Brief Summary
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This study evaluates the effect of four different airtime incentive amounts on short message service (SMS) survey cooperation, response, refusal and contact rates, as compared to control group, in Colombia and Tanzania.

Detailed Description
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Using random digit dialing (RDD) sampling technique, participants were randomized to one of four airtime incentive amounts contingent on them completing the noncommunicable disease risk factor survey. This mobile phone survey will be sent as a short message service (SMS). In SMS surveys, participants use their touch tone key pad to answer written questions. (i.e. If you are male, press 1; If you are female, press 2). This study will be conducted in both Colombia and Tanzania.

Official Title
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A Randomized Controlled Trial of Airtime Incentives to Improve Short Message Service (SMS) Survey Performance in Colombia and Tanzania

Conditions
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Surveys and Questionnaires, Noncommunicable Diseases

Intervention / Treatment
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* Other: 1X airtime incentive
* Other: 2X airtime Incentive
* Other: Lottery airtime incentive


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Access to a mobile phone Greater or equal to 18 years of age In Colombia, conversant in the Spanish language. In Tanzania, conversant in the Swahili language. Exclusion Criteria: Less than 18 years of age

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Participants will be randomized to one of four airtime amounts: 1) no incentive; 2) 1X incentive; 3) 2X incentive or 4) a lottery incentive, in which one out of every 20 participants will receive the incentive.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Control<br>No airtime incentive for completing the survey | |
| Experimental: 1X Incentive<br>1X airtime incentive | Other: 1X airtime incentive<br>* An incentive given in the form of airtime.<br>|
| Experimental: 2X incentive<br>2X airtime incentive | Other: 2X airtime Incentive<br>* An incentive given in the form of airtime.<br>|
| Experimental: Lottery Incentive<br>Lottery airtime incentive where odds of winning lottery are 1 out of 20 | Other: Lottery airtime incentive<br>* An incentive given in the form of airtime.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cooperate Rate #1 | As defined by American Association for Public Opinion Research, cooperation rate is defined as I/(I+P+R) where I is complete interviews, P is partial interviews, and R is refusals and breakoffs. | Through study completion, an average of one month | 
| Response Rate #4 | As defined by American Association for Public Opinion Research, response rate is defined as (I+P)/(I+P+R+eU) where I is complete interviews, P is partial interviews, R is refusals and breakoffs, and eU is the estimated eligible proportion of unknowns. | Through study completion, an average of one month | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Refusal Rate #2 | As defined by American Association for Public Opinion Research, refusal rate is defined as (R)/(I+P+R+eU) where R is refusals and breakoffs, I is complete interviews, P is partial interviews, and eU is the estimated eligible proportion of unknowns. | Through study completion, an average of one month | 
| Contact Rate #2 | As defined by American Association for Public Opinion Research, contact rate is defined as (I+P+R)/(I+P+R+eU) where I is complete interviews, P is partial interviews, R is refusals and breakoffs, and eU is the estimated eligible proportion of unknowns. | Through study completion, an average of one month | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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mobile phone surveys, short message service, incentive