Inexperienced and even experienced survey writers can have difficulty drafting proper survey questions and answers. To avoid unnecessary complications for respondents completing surveys and inaccurate survey results, ensure that survey respondents can choose the survey answer that most accurately indicates their feelings. To do so, write answer choices that are mutually exclusive and collectively exhaustive.
Mutually Exclusive
Mutually exclusive responses have no overlap among answers; each answer represents a distinct choice. For example, your survey question could be, how old are you? Mutually exclusive answer choices are:
- Under 18
- 18-29
- 30-39
- 40-49
- 50-59
- 60-69
- 70 or older
However, what if your answer choices are the following:
- Under 18
- 18-30
- 30-39
- 40-49
- 50-59
- 60-69
- 70 or older.
Those answers are not mutually exclusive, as a 30-year-old would be forced to choose between 18-30 and 30-39. Thus, survey results would not be accurate.
Collectively Exhaustive
Collectively exhaustive means that the answer choices cover all possible responses. Suppose your survey question is what is your favorite day of the week? A set of collectively exhaustive answer choices is:
- Monday
- Tuesday
- Wednesday
- Thursday
- Friday
- Saturday
- Sunday
Since that set contains all seven days of the week, a person will always be able to select his/her favorite day.
An example of a set of answer choices that is not collectively exhaustive is:
- Monday
- Wednesday
- Thursday
- Friday
- Saturday
- Sunday
What would happen if a survey respondent, whose favorite day is Tuesday, sees the second set of answer choices? He/she could not pick Tuesday since Tuesday is not an answer. Whatever answer he/she would give would cause inaccurate survey results.
Sometimes, it might not be possible to include all possible answer choices. Your question could be, what is your favorite social networking website? A proper set of answer choices could be the following:
- X
- Other (Please write in)_______________
The answer choices represent some widely used sites with an option for a person writing in their favorite. Thus, all possible choices would be included. To simplify interpretation, you could include all the most popular options along with an additional write-in choice.
Problems With Both
Answers sets can have problems with both mutually exclusive and collectively exhaustive. Your question could be what is your favorite day of the week? Answer choices could be:
- Monday
- Tuesday
- Thursday
- Friday
- Saturday
- Weekend (Saturday and Sunday)
What if a person’s favorite day is Wednesday? That person would be forced to choose a day that is not his/her favorite day. In addition, what if a person’s favorite day is Saturday? That individual would have to pick between two options.
Final Thoughts
To ensure that survey results can be interpreted correctly, make sure that your survey’s answer options are mutually exclusive and collectively exhaustive. Such answer choices will also make it easier to for people to complete your survey.
Miriam Edelman, MPA, MSSW, is a Washington, D.C.,-based policy professional. Her experience includes policy work for Congress. Miriam’s undergraduate degree is from Barnard College, Columbia University, with majors in political science and urban studies. She has a master’s in public administration from Cornell University, where she was inducted into the national honorary society for public administration. She has a master’s of science in social work (focusing on policy) from Columbia University. She is a commissioner of the DC Commission on Persons with Disabilities. Miriam aims to continue her career in public service. She is especially interested in democracy, civic education, District of Columbia autonomy, diversity, health policy, women’s issues, and disabilities.
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