1. The document summarizes a family of experiments on how documenting design pattern instances impacts source code comprehensibility. 2. The experiments measured the correctness, time, confidence and difficulty participants had in answering comprehension questions about code with and without pattern documentation. 3. The results showed that documenting pattern instances improved correctness of understanding for experienced participants like professionals and PhD students, but not for less experienced participants like undergraduate students. There was no significant difference between textual vs graphical documentation.