It's common in online usability studies to include a few questions after each task. Understanding what a user thinks about how a task went can provide insight into what specific areas of the product are working well or need attention. This section includes a discussion of some of the types of post-task ratings to collect, as well as other strategies to keep in mind when designing the study.
There are several different types of post-task rating scales used in the field today, a few of which are covered here briefly. For a more detailed description of any of these ratings, refer to Tullis and Albert (2008).