What amount of incentive will help raise my survey response rate?

Syosset, New York, July 15, 2003 - Beta Research Corporation, Erdos & Morgan Inc. and McPheters & Company have just completed a multi-phase test to continue our ongoing efforts to increase response rates for mail surveys.

What is currently used?
Incentives for mail studies have used amounts ranging from 25¢ to $1.00 to $2.00 to $5.00. Beta research has tested a variety of incentive amounts (see previous research) including, most recently, two $1 bills vs. a $2 bill.

Who signs the cover letter?
Often times, we overlook the importance of the signature on the letter or the stamp that is used. While we held the stamp constant (regular US 37¢ flag), we alternated two signatures across the studies:

Diane Clark, Director of Research
Beta Research Wave I, Erdos & Morgan Wave II

Nicholas Ferrari, Director of Research
Beta Research Wave II, Erdos & Morgan Wave I

What is being measured?
Our current test compares: 1) the impact of five $1 bills against a single $5 bill among a matched sample for 500 for a variety of questionnaire lengths (see chart below), and 2) a female non-ethnic signature vs. a male ethnic signature.

How is it being conducted?
Hoping to avoid "chance" differences, the same experimental design was set forth for Beta Research Corporation and Erdos and Morgan Inc. utilizing the same general questionnaire for each company.

A study of the demographic data revealed no significant differences.