Brief Summary

Several studies indicate that a survey that adapts personalized design features achieves higher participation rates. A feature can be a personalized cover letter which appears more relevant and interesting for the sample member. In the spirit of adaptive design, this study seeks to establish whether it can be advantageous for participation overall to use cover letters with targeted content and whether the effect on participation of different versions of the cover letter varies in sample subgroups in order to optimize design features in future surveys.

Trial Health

On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment

25,000

participants targeted

Target at P75+ for not_applicable

Timeline

Completed

Started Feb 2017

Geographic Reach

1 country

1 active site

Status

completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

1.3 years study duration

First Submitted

Initial submission to the registry

February 2, 2017

Completed

1 day until next milestone

Study Start

First participant enrolled

February 3, 2017

Completed

5 days until next milestone

First Posted

Study publicly available on registry

February 8, 2017

Completed

3 months until next milestone

Primary Completion

Last participant's last visit for primary outcome

May 19, 2017

Completed

1 year until next milestone

Study Completion

Last participant's last visit for all outcomes

June 1, 2018

Completed

Last Updated

March 24, 2020

Status Verified

March 1, 2020

Enrollment Period

4 months

First QC Date

February 2, 2017

Last Update Submit

March 23, 2020

Conditions

Response Rate

Outcome Measures

Primary Outcomes (1)

Overall response rate
Response rate overall and in the different intervention arms
Up to 3 months (from February 3 2017 to maxium Maj 5 2017)

Secondary Outcomes (1)

Response rate in different subgroups
Up to 3 months (from February 3 2017 to maxium Maj 5 2017)

Study Arms (11)

Standard cover letter

NO INTERVENTION

The group will receive a standard cover letter to the survey that is designed to have broad appeal: You have been randomly selected to participate in a survey of well-being, health and disease among adolescents and adults in Denmark.

Targeted cover letter 1

EXPERIMENTAL

This group will receive a cover letter to the survey including the paragraph: You have been randomly selected to participate in a survey of well-being, health and disease among adolescents and adults in Denmark. The questionnaire will address themes such as stress, alcohol and sleep problems.