I talk with lots of people who design and field their own web surveys. It amazes me how many have never considered sending a reminder out to those they have invited — even to people who are known well by the person doing the survey.
People are often very willing to help, but they are busy and working through lots of messages, and survey invitations are easy to set aside until later. One reminder is often helpful. I almost always send at least one reminder out to survey invitees. In some cases, I will send out a second reminder. In rare cases, a third.
Why send a reminder at all? Perhaps it goes without saying, but more data usually equals better-quality information. Better statistical accuracy is part of that: most people understand that a sample of 300 yields a tighter margin of error than a sample of 100.
But in most cases, response bias will be a bigger threat to the quality of your data than statistical error from sample size. Consider your sample of 300 responses. Did you generate those from 400 invitations (a 75% response rate) or 4,000 invitations (a 7.5% response rate)? The former would give you much greater confidence that those you heard from accurately reflect the larger group that you invited.
What is a “good” response rate? It can vary widely depending on your relationship to the people invited (as well as how interesting and long the survey is, but that’s a topic for another post). Domestic staff/employee surveys often generate a response of 85 percent or more. However, for internationally distributed missionary staff, a response of 60 percent is healthy. For audiences with an established interest in your work (event attenders, network members), a 35-percent response is decent. For other audiences, expect something lower. One online survey supplier’s analysis of nearly 200 surveys indicated a median respose rate of 26 percent.
So, do reminders substantially increase response to surveys? Absolutely. Online survey provider Vovici blogs, “Following up survey invitations with reminders is the most dramatic way to improve your response rate.” They show results from one survey where the response rate rose from 14 percent to 23, 28 and 33 percent after subsequent reminders.
My experience has been similar. I find that survey invitations and reminders have something like a “half-life” effect. If your initial invitation generates X responses, you can expect a first reminder to produce an additional .50X responses, a second reminder .25X responses, and so on.
I disagree with survey provider Zoomerang’s suggestion of sending a series of three reminders — especially if the audience is people you know — but I do agree with their statement, “Think of your first email reminder as a favor, not an annoyance.” I recommend sending at least one reminder for virtually any survey, with a second reminder only if you feel that your response rate is troublesome and you need that extra .25X of input.
At least Zoomerang provides a sample reminder template you can use. I agree that you should keep reminders short — shorter than the original invitation. With any invitation or reminder, you will do well to keep the survey link “above the fold” (to use a phrase from old-time print journalism), meaning that it should be visible to readers without their having to scroll down through your message.
I also find that it very helpful to use list managers in sending survey reminders. Most online providers will have an option where you can send only to those members of your invitation list who haven’t responded. Not only does this keep from annoying those who already did respond, but you can word the reminder much more directly (and personally, with customized name fields). So, instead of saying:
“Dear friend — If you haven’t already responded to our survey, please do so today.”
You can say:
“Dear Zach — I notice that you haven’t responded to our survey yet. No problem, I’m sure you’re busy. But it would be great to get your input today. Here’s the link.”
Take care in using the above approach — if you have promised anonymity (not just confidentiality), as in an employee survey, opt for the generic reminder.
When to send a reminder? If your schedule is not pressing, send a reminder out 5-10 days after the previous contact. I recommend varying the time of day and week in order to connect with different kinds of people. If I sent the initial invitation on a Monday morning, I might send the reminder the following Wednesday afternoon.