Sentence Completion Survey Technique in User Research
What is SCT
The sentence completion technique (SCT) is a method of research where participants have to finish a sentence in order to measure their thoughts, feelings, and experiences. While researching how language variations of the sentence stems affect responses, researchers found that native speakers were better able to express emotion and give longer answers. Psychological studies done in the 1940s discovered that first-person sentence stems produced more projection than impersonal sentence stems, and neutral sentence stems had a higher level of projection than positive or negative sentence stems. The length of the stem and the length of the total test affect the motivation and fatigue of the participant.
SCT comparing with other user research methods
SCT is efficient and can collect a large number of responses in a short time. This technique is a reliable way to gather accurate, helpful data from a large number of respondents. It also has the benefit of being attractive to respondents, as it is described as ‘fun’ or ‘easy’ to complete. SCT studies don’t need to be explicitly based on any specific theory of user experience. Usability testing has the benefit of providing precise information about usability issues, but a smaller sample size. Interviews and focus groups have the benefit of providing detailed, unique insights, but require a larger sample size. The text also highlights that accessibility issues should be explored more thoroughly.
Types of sentence stems in SCT
A generic sentence stem usually provides an introduction to the survey and serves as an onboarding process. It typically produces stereotypical ideas, but can be useful for emphasizing main issues or needs.
Comparative sentence stems are sentences that ask participants to compare two different things, such as a petrol car and electric car. It produces higher amounts of data and seemed easier to answer. It can be used in SCT to help uncover feelings, attitudes, motivations, needs or frustrations.
Redundant sentence stems are sentences that ask the same question twice, with slight variations. They can be used to prompt participants to provide more depth into their answers and often lead to a higher level of abstraction in the rationale of their experiences. They also tend to lead to more hedonic insights.
Tips for designing effective SCT
- Brainstorm sentence stems for the topics you want to study and then have a diverse group of people test them to make sure the wording is clear and unambiguous.
- Use a general question as a “scaffolding” or structure for the study.
- Use comparative items when there is an equivalent experience to compare. This might mean comparing online meetings to in-person meetings, or 2 websites.
- Duplicate items when seeking out more information related to the topic. You can use two similar items about frustrations experienced with a product to get different ideas and to emphasize more hedonic ideas.
- Be careful when using “extreme” items. These items can lead to less response and fewer ideas, but at the same time can lead to more unique and creative results. If you decide to include these types of sentences, it’s better to make them optional.
