OASIS Conventions Series, Part 3: The General Rules for Completing OASIS

by Lori A. Marmon, PT, MBA, COS-C

The OASIS Conventions—the general rules that guide accurate OASIS data collection—are outlined in Chapter 1 of the OASIS-E1 Guidance Manual. They are also summarized in a popular, quick-reference resource created by OASIS Answers: the INSTANT OASIS Answers Book, referenced by many as simply “the little brown book”.

The INSTANT OASIS Answers Book includes all conventions for completing OASIS, including those already covered in part 1 (Assessment Strategies for Accurate OASIS Data Collection) and part 2 (Defining Assistance in OASIS—What Counts and What Doesn’t) of this series, as well as item-specific guidance and references to CMS policies. It’s a user-friendly and up-to-date tool for both new and experienced clinicians.

In Part 3 of our OASIS Convention series, we’re focusing on the concept of the “Day of Assessment” and how it impacts OASIS data collection.

The “Day of Assessment” convention defines the time period under consideration—also known as the look-back period—for each OASIS item. This doesn’t refer only to what is observed in the moment during the visit. Instead, it includes:

The 24 hours immediately preceding the home visit, and
The time the clinician spends in the home conducting the assessment.

For most OASIS items, this entire period is considered the “Day of Assessment.”

If an OASIS item has a look-back period other than the day of assessment, this item-specific lookback period will be specified in the guidance for that item. If no specific period is defined, then by default, the time used for collecting information will be the 24 hours before the visit plus the duration of the home assessment itself.

For additional clarification on this timeframe and how collaboration fits within it, refer to CMS OASIS Q&As Category 2, Q15.3.3.

Join us at a Blueprint for OASIS Accuracy workshop and immerse yourself in the practical application of these conventions with expert-led guidance and peer collaboration.