We are being challenged by a regulatory body to provide evidence that users can understand the contraindication and warning statements in our Instructions for Use (IFU). I'm not sure how to go about this. The often-used "readability" metrics (e.g. "Flesch reading ease" or "Flesch-Kincaid Grade Level") are inappropriate, as they rely on syllables-per-word, and there are some unavoidable multi-syllable words due to the nature of the device (and by the "canned" warnings from guidances). I've thought about a study where subjects read each statement aloud, and self-report whether they understand or not, but there are many specific contraindications that most people would not understand unless they had the particular condition. (The device is for home-use, and even the word "contraindication" may be problematic...) Questions for discussion: - Anyone else had to demonstrate user comprehension of contraindications/warnings? - How would you go about providing such evidence?