Thanks for engaging! Our passages are a mix of public domain passages and in-house authored material which are specced to a long list of requirements. This allows us to create passages spanning a rich variety of characteristics, including genres, contexts, settings, cultures, socioeconomic backgrounds, household family set-ups (e.g., single-parent households, grandparent-led households), etc. We also rigorously vet our content using AI evaluators from Learning Commons, which were created using a golden set of inputs from a panel of experienced educators.

I also have several years' experience writing standardized test preparatory materials. Ultimately the reading comprehension modules serve the end goal of teaching students discrete skills, which roll up into standards. Those standards are (as you point out) the main focus of standardized, summative tests.

We encourage students to read real books! We have an AI writing tool that integrates with schools' novel studies curricula to generate a wide variety of prompts so that students can engage in long form writing about the books they are reading.