Nonresponse bias sample mailing nonrespondents (households without telephone numbers)

Fed Ex/Priority mail letter for fourth mailing

U.S. Department of the Interior Letterhead

Dear Resident:

Several weeks ago, we sent you a survey to complete. Your response is very important for the research project. We have enclosed a shorter version of the survey. As a token of our appreciation for completing this shorter survey, we will send you $20 when you return your completed survey or take the survey on the internet.

Even if you have never heard of the Klamath River, your opinions are very important to this study. This study is funded by the U.S. Department of the Interior and is being conducted by RTI International, an independent, not-for-profit research institute.

YOU CAN TAKE THE SURVEY ON THE INTERNET! You can take this survey through a web site instead of filling out the paper survey. Please complete the survey by visiting the following web site: https://XXXX.rti.org/. You will need an ID and password in order to log in to this website. If you log on to the website but do not finish the survey, you can use your ID and password to log back in and complete the survey.

Your unique ID and password are: ID: XXXXXX Password: XXXXXXX

If possible, please have the adult age 21 or older in your household with the most recent birthday fill out the survey. If that person cannot complete the survey, please have another adult age 21 or older in your household fill it out.

Your name and address will not be associated with your individual answers, and the results of the survey will be reported as group averages only.

Taking part in this survey is voluntary. If you agree to participate, we ask you to answer all of the questions as honestly as you can, but if you do not want to answer a specific question, please skip it and go on to the next question. If you have any questions about the study, you may call Carol Mansfield at 1-866-XXX-XXXX (a toll-free number) or email [email protected]. If you have any questions about your rights as a study participant, you may call RTI’s Office of Research Protection at 1-866-214-2043 (also toll-free).

Thank you for your participation.

Sincerely,

Benjamin Simon

Project Director, Department of the Interior