What Is Nonresponse Bias And How Can You Minimise It?

If you’re to deliver an effective survey, you’ll need to identify what you want to measure, the audience you want to target and your choice of distribution method to reach that audience.

However, if after all this careful planning you find that your survey response rate is much lower than you expected, you need to be asking yourself, what could be the cause of this?

Well, one of the biggest factors could be nonresponse bias.

Read on to find out more about this issue, its causes, why it can be problematic and ways to reduce nonresponse bias in your own surveys.

What causes nonresponse bias?

Besides requests for sensitive information, there are many more issues that can cause nonresponse bias.

Here are some of the key ones.

Poor survey design

From the length and presentation of your survey to how easy it is to understand and answer. There’s a lot of issues to do with your survey design that can cause respondents to drop out and fail to complete your survey.

Subsequently, you need to make sure your survey is as clear, concise and engaging as you can make it.

Be sure to follow and include some survey design best practices, to make your next survey is as good as it can be.

Incorrect target audience

One of the first things you need to think about in your survey project, is the audience you’re targeting.

Make sure that audience is relevant to the survey you’re looking to send out.

For example, if you were issuing a survey to canvas views about a new flavour of dog food, you wouldn’t want to accidentally include cat owners in your survey distribution list.

Failed deliveries

Unfortunately, when you send your surveys, some will always end up going directly into a spam folder. However, if you’ve not set up your sending options in the right way, you may not even know if your survey wasn’t received and it will be just recorded as a nonresponse.

To help with that some distribution options such as email enable open tracking options, to let you know if your email was opened, how many survey click throughs you got, and who responded to your survey, so you can be more accurate in your recording.

Refusals

There can be a lot going on in people’s lives, so, no matter how good your survey, there’s always likely to be some people who will just say ‘no’ to completing it.

It could be a bad day or time for them, or they may just not want to do it. However, bear in mind that just because they said “no” today, it doesn’t mean they won’t take one of your surveys another time.

Accidental omission

Sometimes some people will simply forget to complete your survey.

While it’s difficult to prevent this from happening, in most cases this will only affect a smaller number of your nonresponses.

Why is nonresponse bias a problem?

The problem with nonresponse bias is that it can lead to inconclusive results, which prevents your survey from meeting its objective, no matter what your survey’s goal.

For example, let’s say you wanted to gather data about a particular product feature, to find out whether or not it was still adding value to your product.

If an insufficient number of your sample completed your survey, you might not have sufficient data to make an informed decision on whether to keep the feature as it is, improve it, or go in another direction completely.

Survey data is only at its most informative and useful when you’re able to see the complete picture of something. So, limiting your nonresponse bias not only has an impact on your survey responses, but on your decision making too.

How to reduce nonresponse bias

Having got up to speed with nonresponse bias, it’s causes and why it’s a problem, we’re sure many of you will be keen to know how to keep it to an absolute minimum in your surveys.

Well, read on for some tips about how to reduce nonresponse bias.

Keep your surveys simple and concise

Short and simple is the key here.

In fact, studies show that longer surveys on average lose more than three times as many respondents compared to a survey that is less than five minutes long.

The problem with including too many survey questions, is that your customer may not finish their responses, or want to begin your survey in the first place. Consider making your survey no more than five minutes long with 10 questions at most.

Pre test your survey

It is really important to ensure that your survey and your survey invites are able to run smoothly on any medium or device that your respondents might potentially use. This is because respondents are more likely to ignore any survey requests which have long loading times, or the questions don’t fit accurately with the screen size they’re looking at.

Consequently, it’s prudent to consider all the possible communications software and devices your survey may be run on and pre-test your surveys on each of these, to try and ensure it runs as smoothly on as many of these as you can.

Set participant expectations

To help minimise nonresponse bias, it’s good practice to communicate to your customer what they should expect from your survey, either through an earlier email or in your survey introduction message.

You need to outline your survey’s goal, approximate time it will take to complete and any details about anonymity or confidentiality that’s included in your survey.

Re-examine your survey timing and distribution methods

Your survey distribution timing and method can also make a difference to your volume of nonresponses.

From whether you’re targeting an internal or external or B2B or B2C audience. When it comes to the best times to send your survey, there’s lots of factors that can influence your success. However, it can be helpful to test out a range of different days and times and see what best works for you.

Whether you use email, SMS or a weblink, or have more success through social media or QR codes. Similarly, to altering your timings, different survey distribution methods can work better with different audience groups.

Once again, it can also be helpful to test out different channels with your audience to see what generates the best response rate, while minimising your nonresponses.

Offer an incentive to complete your survey

Always try to communicate to respondents how they will benefit from taking your survey. It could be as simple as telling them how their feedback will be used and the pain points this will solve for them moving forward.

Alternatively, if you’re targeting a consumer audience, you might like to offer a monetary incentive for them to complete your survey.

For example, you might like to offer a discount on a future purchase they make with you, or an incentive for referring a friend.

Issue reminders

Busy customers can easily put your survey on their to-do's list, but then forget to complete it. So, being able to send a few reminders can be really beneficial in boosting the number of completed responses you’re able to gather.

Carefully make a note of when you send reminders and be mindful to space them out, so you don’t harass people on your contact lists, especially those who’ve already completed your survey.

Remember to close the feedback loop

Be sure to thank those that complete your survey, letting them know how much you appreciate their time and feedback. And depending on the nature of your survey, you may give a brief indication of what you hope to do with that information.

Ultimately, when a respondent feels that they have been heard and appreciated, then they’ll be more likely to complete another one of your surveys in the future.

Get better results when sending your surveys

We hope you found this blog interesting. Having provided an overview of nonresponse bias, it’s causes and ways to reduce it, we hope you will be able to incorporate some of this advice in your own surveys

While the extra checks and tasks are likely to add a bit more time on to your survey project, the boost to your survey response numbers and the quality of your data should make up for this.