Each time the reader reaches the cue, ask for an explanation of what that section means. You should use a different type of protocol testing when evaluating long documents, like booklets and regulations. In this type of protocol test, not only do you test for comprehension, but you are also make notes about the way the reader uses the document. For instance you would note how often a reader has to flip from page to page, to find references. In other words, you test the document as a whole, not just individual paragraphs.
Protocol testing is rather time consuming.
Tested letters eliminates needless phone calls and correspondence asking for clarification of the original letter. For instance Veterans Benefits Administration tested a letter in which readers appeared to understand every word. However, when asked what they would do if they got this letter, most people said they would call VBA's toll-free number. The letter was about a replacement check sent because the original check was now out of date. Readers indicated that they would call if they didn't receive the check the same time as the letter.