Survey: Post-task
The post-task survey is a research technique commonly used within usability testing. It consists of asking the participant short, specific questions immediately after they have completed (or tried to complete) a particular task or scenario with the product. Unlike post-test surveys, which are given at the end of the whole session, it captures the user's immediate impression of that specific interaction.
What it is
Main objective
To capture the user's immediate subjective perception of the interaction that just took place, before that perception fades or blends with later tasks.
Detailed description
This method belongs to self-reported metrics. Tom Tullis and Bill Albert were central to formalising these metrics, and they open their chapter on them with: "Perhaps the most obvious way to learn about the usability of something is to ask users to tell you about their experience with it" (Tullis and Albert, 2008, p. 123). Although it has roots in psychometrics and traditional survey research, asking right after the task addresses a memory problem: as Rubin and Chisnell put it, participants recall their reactions and feelings more easily because they have just completed the tasks they are being asked about (Rubin and Chisnell, 2008, p. 193).
It strictly measures attitudes: what people say they feel or think. Tullis and Albert set it apart from what is observed: it rests on what users share about their experience, not on what the specialist measures about their actual behaviour. It produces mainly quantitative data, scale ratings (for example, a 1 to 5 or 1 to 7 rating of difficulty), which can be complemented with spoken or written comments about specific problems or the reasons behind what the participant did.
The process is built into the protocol of a usability test:
- Task definition: the user receives a scenario and carries out the action in the prototype or product.
- Immediate administration: right after the task ends, and before the next one starts, the survey is shown.
- Question format: questions should be concise. Rubin and Chisnell advise being "concise and precise" in what you ask and including only the items each participant needs to answer (Rubin and Chisnell, 2008, p. 193).
- Scales: Likert scales (for example, 1 to 5 or 1 to 7) or binary-choice questions.
- Analysis: average scores are analysed per task to find which specific flows are problematic, regardless of the technical success rate.
When it fits
During a usability test, moderated or unmoderated, right after each task ends and before the next one starts.
Use cases
Effort level
LowRecommended number of users
6 to 8 participants per iteration in formative studies. In summative studies, 50 to 100; 20 is possible, but the variance is high and the findings are hard to generalise, and for subtle design changes at least 100 is advisable (Tullis and Albert, 2008, p. 59).What you gain and what you give up
Advantages
Disadvantages
How it is applied
Metrics
Practical example
During the migration of a web portal, the team measured satisfaction with each task every week using an ease-of-use survey, alongside effectiveness (how many people attempted the task and how many completed it) and efficiency (time and number of clicks), to see whether the changes were improving the product (Monge, Repain and Pinilla, 2022, p. 250).