# How do I calculate the response rate to my online survey?

A not uncommon mistake in calculating response rates is to work it out as the number of returned questionnaires in the case of paper as a percentage of questionnaire sent or handed and for online questionnaire, the number completed as a percentage of invitations sent out via email.  This is an incorrect approach and as a result the calculated response rate will be lower.

In the case of a paper questionnaire mail out 500 questionnaires are sent out. It’s unlikely however, that all 500 will be received due to the address being out of date, the recipient is untraceable or the recipient should not have been included in the survey. This is know as “Out of scope.”

Example APostal survey

Type 1 diabetes patients selected from clinic register:    N=298 = 100%

Questionnaires sent out:                                                        N=298  = 100%

Out of scope

(i) Moved or non traceable:                                                   N=16

(ii) Were not type 1 diabetes:                                                 N=4

Total out of scope:                                                                     N=20 = 6.71%

Remaining in scope patients:                                                  N=298 – 20 = 278 = 100%

Total number of non returned questionnaires:                   N=39 = 14.02%

Final response rate:                                                                   N=278 (100%) – 39(14.02%) = 85.98%

Example B: Online survey

Email invite to complete  online survey:           N=150 = 100%

Out of scope

(ii)  Should not have been included:                  N=5

Total out of scope:                                                  N=15  = 10%

Remaining in scope:                                              N=150 = 15 = 135 = 100%

Total non response

(i) Deleted email:                                                   N=5

(ii) Survey not completed:                                   N=5

Total non response:                                              N=10 (7.41%)

Final response rate:                                              100% – 7.41% = 92.59%

These are the basic approaches to calculating survey response rates. You can for example, if your database enables segmentation such as age, gender and other relevant characteristics, you can determine response rates for each.

If you would like to follow our postings why not link up to us, for example through the RSS feed.