In a survey, data is collected by participants answering a series of questions. Unfortunately, poorly designed surveys can negatively affect the results of a study. For example, leading questions influence participants' answers so that their original views are not reflected. This kind of influence is called bias in survey questions. A variety of factors contribute to bias.

Double-Barreled Questions

A double-barreled question causes the reader to answer two questions with the same single answer, thereby disallowing for the necessary nuance to answer both questions separately. To avoid this issue, verify the question and, if needed, split it into two or more questions.

Biased Question	Unbiased Question
How likely are you to recommend medieval fantasy books and movies ?	How likely are you to recommend medieval fantasy books?
	How likely are you to recommend medieval fantasy movies?
How much do you enjoy playing video games and watching movies?	How much do you enjoy playing video games?
	How much do you enjoy watching movies?

Question Order

This bias happens when questions that are related are not presented in logical order. For example, questions asked early in a survey can influence how participants answer questions later in the survey.

Biased Order
$1.$ What is your least favorite math subject?
$2.$ How much do you enjoy math?

In this case, asking about the participant's least favorite math subject will have a strong influence on how they respond if later asked about their feelings towards math in general. Using the inverse order will produce a fairer response.

Unbiased Order
$1.$ How much do you enjoy math?
$2.$ What is your least favorite math subject?

Depending on the situation, randomization can also be applied to avoid this bias.

Leading Questions

A leading question leads respondents to answer in a specific way desired by the surveyor. Leading questions can be written either intentionally or unintentionally. To avoid this bias, ask questions clearly and do not use words that encourage specific answers.

Biased Question	Unbiased Question
Do you always consume fast food?	How often do you consume fast food?
How healthy are you?	How would you rate your health?

Keep in mind that these are just a few of the factors that can lead to bias in survey questions. Other factors such as language, length of the survey, and asking answerable questions should also be considered to avoid biases in questions.