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Tips to avoid Non-response Bias

Market research 04 12
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There are two categories of Biases, these are, Non-response Bias and Response Bias. Non-response bias focuses on the group of participants who do not complete the survey. Response bias, on the other hand, refers to the participants who respond to your survey.

Response Bias occurs when participants provide inaccurate answers to the survey or the responses are recorded incorrectly.

  • The error occurs because of a factor in the research that makes the result different from the opinions of the participants. 
  • The respondent may not be aware that they are not answering the survey the way the researchers intended. 

Non-response Bias occurs when a percentage of people are unwilling or unable to respond to a survey. The participants don’t understand, forget to complete the survey, or are simply unwilling to take it. 

  • The error is caused by the absence of participants and not from collecting erroneous data.
  • It is the difference between the true mean values of the total no. of people who are sent the survey and the true mean value of the total no. of respondents. 

Non-response Bias can be caused due to different factors. Some of the factors that you should be aware of are listed as follows.

Tips to avoid Non response bias1


What causes Non-Response Bias?

  • Participants are more likely to drop the survey if it is too long or difficult to understand. If the survey takes longer than 7 to 8 minutes, the completion rate drops between 5 to 20%. 
  • Some people you sent the survey to, may not be the right audience for your survey. They may not want to provide you with any personal information or maybe they don’t have time. 
  • Some people may refuse to participate in your survey. They may not be willing to take a survey asking for sensitive information. People may refuse to answer because you may be asking for embarrassing information. Let’s say the survey is about taxpayers, the non-law-abiding citizen won’t be thrilled to respond to your survey.
  • Your survey may not have reached the members of the sample. For instance, it could be that the email survey you sent ended up in the spam folder of the recipient. This is recorded as a non-responsive bias. 
  • Or, following the previous point, your email survey may not be mobile-friendly. Most business sector employees prefer to respond to surveys with mobile devices. If your survey can not be displayed on mobile devices, people may not respond to it. This will lead to a drop in response rate and cause non-response bias. 
  • It could also be that they forgot about completing the survey. It could be that they were busy and distracted which led to them forgetting about the survey. Such occurrences can also result in non-responsive bias.
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How can you avoid Non-response Bias?

It is impossible to wipe out non-responsive bias because you cannot force people to respond. There are few ways that can help you avoid the issue. 

Ensure your Survey runs smoothly

People are likely to drop your survey if:

  • Loading time is long
  • Questions don’t fit the screen 
  • They have to adjust the survey so it is compatible with their device

Ensure that your survey runs smoothly across any device your audience may use. Test all the survey and its invites on all devices before you send them out to the respondents. 

Keep Survey length short

As mentioned, a long survey can cause the participant to drop the survey. The survey length is a deciding factor if they will complete the survey or not. Don’t make it too lengthy. A survey of 30 questions takes up to 7 to 8 minutes to complete and is also considered the ideal survey length. 

Extend your Survey Collection period

Limiting the time of the survey can affect the data collection. The non-responsive bias may increase if you are not if you have a fixed deadline for the survey. It is better to extend the survey to a week or two. 

With online surveys, the flexible timeline can be of advantage. The participants can choose to respond to the survey whenever they want according to their own schedule. 

Send reminder 

Sending reminders during the survey period can increase the chance of receiving a response from the potential respondent. Don’t send too many reminders. 

You can send the first reminder after a few days of sending the survey, or in the middle of the survey period. Then you can send another one near the end of the survey period. Only send reminders to those who have not yet responded.

“Prefer not to answer”

The option of ‘prefer not to answer’ gives respondents the freedom to skip any question they don’t want to answer. This way the participants won’t feel pressured to provide the information they don’t want to share. People would prefer to abandon the survey that makes them feel uncomfortable. 

Keep it confidential

Whenever you want to collect data from your participants, which is personal, you need to assure them that the collected data will be kept confidential. 

When your survey asks questions about sensitive topics, ensure that participants know that the information they provide will be read as a whole. Along with the fact that the identity will remain confidential. 

Offer Incentives to the Participants

An incentive of some sort can motivate the participants to complete the survey. People often refuse to take the survey because they don’t want to spend their time answering questions. 

You can range the incentive depending on the length of the survey and the information you are trying to collect. Offering incentives may make respondents feel that taking the survey would be worth their time.

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Non-response errors occur when you don’t have sufficient answers to your survey. There are two types of non-response errors. 

  • Complete non-response errors occur when the respondent is unavailable or refuses to take the survey. 
  • Partial non-response errors occur when the respondent gives you incomplete information.

There are four types of errors that you need to consider when you design a survey

  • Coverage error: the opportunity you need to give to all potential respondents to take the survey. 
  • Sampling error: when a sample is too small to accurately represent the population. 
  • Response rate error: implies getting responses back from the members of the sample you have sent the survey.
  • Measurement error

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This post is also available in French.