With Custom Feedback an evaluation is made of the answer given and feedback is displayed depending on the evaluation. The evaluation usually checks a score against a particular value, and feedback is displayed depending on whether or not conditions that you have set are met.
In this example the aim is to show seperate feedback for different groups of questions. The questions have been labelled as either Geography or History and the feedback shows the scores that the quiz taker has achieved in each group as well as the overall score. This is useful to show potential areas of weakness.
NB There are no conditions set so the evaluation is always true and the feedback is always shown.
The second piece of feedback evaluates the geography score, and if it is less than 20 the condition evaluates to 'true' and so displays the simple message.
The third piece of feedback does the same, but for the history score.
The Condition can contain And, Or and Not nodes, so evaluations can take place that depend on multiple scores, or one thing being true and another being false, or any one of a number of things being true. The feedback can also redirect the user to another part of the quiz - maybe to bounce the user back into the question if he answered incorrectly, or to skip a question based on a response given by the user. You can find out more about this in Skipping and Branching.
You can try out this sample quiz in your browser [] or download the source file (.qwz)to have a close look at the set up [].