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What Is Nonresponse Bias? (And How to Avoid It)

Check out these survey best practices to improve your survey questions, increase your number of respondents and avoid nonresponse bias.

Sending customer surveys and polls can help you learn about your business, marketing, and customers to help you build customer relationships and encourage loyalty.

Learning about how your customers feel about your business and its products and services can help you avoid bad reviews that damage your reputation while making your customers feel like you care about their experiences.

Customer feedback can help your business grow, allowing you to collect valuable feedback to understand what areas of your business need improvement and helping you create beneficial customer feedback loops. But unfortunately, not all of your customers will respond to requests for feedback.

When customers choose not to complete your surveys, polls, or questionnaires, it's called nonresponse bias. Unfortunately, you can't control who will be willing to participate, but you can find ways to increase engagement and collect more customer feedback.

What is nonresponse bias?

Nonresponse bias occurs when participants in a survey don't respond to a question or the entire survey.

This type of survey bias differs from other types of biases, like voluntary response bias, in which survey participants are self-selected and choose to respond because they have strong opinions. With nonresponse bias, participants may choose not to respond because they don't have any opinions or don't want to respond to your survey.

In addition, response bias means customers may not answer truthfully for various reasons. For example, if you include an offer with the completion of the survey, customers may not read the questions before responding because they're trying to get it over with to get their offer.

Both response and nonresponse bias can be detrimental to your results. For example, response bias can give you inaccurate data, forcing you to focus on areas of your business that may not need help. Meanwhile, nonresponse bias affects your sample size, and the smaller your sample size, the less likely the data collected is correct.

There are many reasons for nonresponse bias. For example, potential respondents may be unable to answer questions because of how they are asked or because they don't want to provide you with personal information. Potential respondents could provide inaccurate, false answers simply because they don't want to answer the questions truthfully.

How does nonresponse bias occur?

Nonresponse bias can affect anything, including requests for customer reviews and feedback that can help you improve their experiences and your marketing campaigns. There are several reasons why nonresponse bias occurs, including the following:

Bad design

Bad design can increase nonresponse bias because it makes it difficult for customers to complete. When you create a survey, you should consider its complete design, including how long it will take to complete.

Potential respondents will be less likely to complete your survey if it's too long, especially if you send it via email and they're completing it in their free time. Your survey should be as short as possible to help you reach your goals and learn more about your customers.

Incorrect audience

Your business likely targets multiple customer segments. If you target the wrong audience with your survey, potential respondents may choose not to respond because it's irrelevant.

For instance, if you're an e-commerce company, you might ask the wrong survey questions about a particular product to the wrong customers. If customers have never purchased the product in question, they won't respond to your survey.

Personal reasons

Some of your customers may simply choose not to complete surveys. Your customers are busy and may feel as though they don't have the time to provide your business with answers. Of course, customers can choose not to respond to surveys when it's a bad time for them and then change their minds later.

In addition to not wanting to complete your survey, your survey may ask questions that make it so customers can't respond. For example, if your survey asks for personal information people want to keep private, they'll be less likely to respond.

6 ways to avoid nonresponse bias in your surveys

Unfortunately, you can't always avoid nonresponse bias in your surveys because some customers may choose not to answer your questions. Still, you can increase engagement in a few ways to reduce nonresponse bias and ensure you get the most out of your questionnaires. Here are a few ways to avoid nonresponse bias:

Test designs

Most companies send customer surveys via email because it's the easiest survey method for customers and businesses. Therefore, you should always test your email design to ensure it's easy to understand and looks good on all devices, including desktops, laptops, and smartphones. Remember, customers are more likely to ignore your requests if surveys take too long to load or don't load properly, so you should always test your surveys before sending or publishing them.

Tell customers what to expect

Before sending customers a survey, you should introduce the survey and set customer expectations early in the process. Always tell your customers the purpose of your survey and why they should complete it with the most accurate answers. You can also include how long the survey will take to complete to help them decide whether they should start it now or later.

Segment your audience

Sending your survey to the correct audience is crucial, so you should leverage customer data whenever possible. For example, if you only want to survey customers who have interacted with your customer service team, there's no reason to send surveys to all of your customers. Before sending your email survey, identify your target audience to ensure they can answer all your questions.

Use multiple-choice questions

While short answer questions can provide more information about your customers' experiences, multiple-choice questions are easier and more convenient to answer. In addition, having only a few pieces of data to analyze later will make it easier to understand your data.

Follow up with potential respondents

Not all of your customers will be willing or able to complete your survey as soon as it reaches their inboxes. Therefore, it's a good idea to send reminders to individuals who haven't started their surveys after a few days. Your reminder shouldn't be too pushy, but it should remind customers you're waiting for their responses and how they will help your business.


Many customers don't want to answer survey questions because it means taking up their valuable time. Incentivizing customers with offers upon completion can help you get more responses and ensure customers are actively engaged in the survey.

Luckily, there are many ways to incentivize customers to complete your survey, including offers and discounts. Of course, you should be careful when incentivizing customers to complete your survey. However, some customers may provide inaccurate or false answers to get through the process faster because they're only doing it for the incentive.

How to create more engaging surveys to get responses

Reducing nonresponse bias is crucial to the success of your survey. Your main priority when developing customer surveys should be getting customers' responses. If customers aren't responding, you won't have enough data to make critical business decisions. Here are a few steps to follow to create more engaging surveys:

Identify your goals

Identifying your goals will help you craft the right questions for your survey while keeping it short. For example, if you want to learn whether customers are happy with your customer service team and efforts, you can create goals that focus most on customer satisfaction.

If you want to learn about how customers feel about a certain product or service offering, you should keep your survey focused on questions that pertain only to those.

Determine your target audience

Once you've identified your survey goals, you can start identifying your target audience. Of course, not all your customers are ideal potential respondents, so you'll need to segment your subscribers into groups to ensure accurate survey results. For example, if you want to learn about a specific product, you should only target customers who have purchased it.

Make it short

When drafting your survey questions, keep them short and sweet. Your survey should take at most a few minutes to complete, and questions should be simple enough that customers don't need more time to think about them before answering.

Test it

Before sending your survey to your audience, consider testing it with a small sample size. You can send it to a small portion of your audience to determine whether customers are opening the emails, starting, and completing the surveys. If they aren't sending responses, you may need to go back to the drawing board to redesign your survey.

What should you do with your survey results?

Once your survey results are in, it's time to analyze the data. You can use several tools to do this, including a simple spreadsheet with responses that make it easy to understand your data. With a spreadsheet, you can create graphs to understand the most common answers to questions and use the data to make important business decisions.

Mailchimp makes it easy to send customer surveys, requests for reviews and testimonials, and polls to help you learn more about your customers. Create, design, and send your campaign to begin collecting results.

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