Automated Impairment Rating: The Science Behind RateFast

RateFast automates the impairment rating process, giving providers and injured workers the ability to generate accurate analyses of occupational injuries based on the AMA Guides to Impairment Rating.

But how is it done?

Listen to the podcast or keep reading to discover how CPA Josh Moore applies knowledge from accounting to the development of the RateFast impairment rating system.

Josh Moore met with RateFast CEO John Alchemy coincidentally. They quickly discovered a mutual passion for the process of creating organizational systems, Josh with his background in California public accounting, and John with his in workers’ compensation.

Several shared coffee breaks later, and Josh Moore found himself on the RateFast team, developing algorithms that would determine impairment ratings for injuries to the upper and lower extremities—all in accordance with Chapters 16 and 17 of the AMA Guides to Impairment Rating.

Josh was tasked with integrating the user’s inputs (for example, the physician’s measurements of the range of motion for a patient’s injured shoulder) with the rules of the AMA Guides to return correct results. The tasks for the project ranged from double-checking that the outputs were rounded to the correct decimal, to combining complex formulas, to tailoring the user’s experience of entering data into the impairment engine.

Josh works with a larger team within RateFast consisting of Professor Jerry Artz, PhD, Hamline University,  dept of Physics and Marten Thompson, a now graduate of Hamline university with a double major in math and physics. Jerry works with Chapter 15, The Spine. Marten performs statistical research for Ratefast, and does more research and design on special projects for proof of concept before we place things into production. It’s a very tight and integrated team, built on trust, intelligence, and collaboration.

Validators Versus Calculators

RateFast’s engine runs on something called a “validator” as opposed to a calculator. What’s the difference you ask? A calculator simply puts something in and turns something out. A validator is like a money exchange machine: putting in a piece of paper that happens to be the same size as a dollar bill does not mean you are going to get any change back. With a validator, multiple checks are performed on the paper to ensure the paper placed in the machine is indeed money.

It is the same concept with the RateFast impairment engines, which are validators. The measurements and information from the physician’s examination of the patient are entered into RateFast, and then the data is tested for validity, reproducibility, probability of accuracy, chance independence, and so forth. A validator takes a piece of data, analyzes it according to the relevant specifications, and finally rejects the data point or moves it forward.

For example, if a knee is injured and the impairment rating is to be provided based on a loss of motion, then the rating must contain three measurements. They must be within 10% of one another to be considered valid. (A calculator, on the other hand, will just provide an output, rather than checking for accuracy and consistency in the clinical data set.)

RateFast also runs logic called “variable thread analytic computation”, or VTAC for short. It’s a decision-making system that “gates” information which can promote or arrest the movement of data through the rating process. Variable thread means we can consider multiple body part logic rule sets in parallel, and ensure the movement is compliant with the AMA Guides.

For instance, for injuries involving the upper extremity, physicians often perform a grip or pinch test. In grip or pinch, the range of motion measurements required by the AMA Guides must be full and complete, and there can be no pain. If the physician using RateFast does not meet these conditions, then they cannot proceed with the grip-pinch test. A provider performing the exam with RateFast or a similar validator needs to manually remember how to perform the examination and check their test results for validity, or else risk turning in a bad impairment rating.

Impairment and Taxes

For Josh, there are important parallels between tax returns and impairment ratings. When you fill out your tax return, you need to have your receipts. In the workers’ comp exam room, you need to properly record your data and measurements.

When entering those measurements, you need to know what’s allowed and what isn’t allowed for different ranges of data—sort of like tax basis for income levels, or alternative minimum tax owed.

Similarly, ratings have maximums and minimums and allowances for which the data set may or may not qualify. For example, a patient’s injury might receive an extra 0.5% Whole Person Impairment point if the limitation of motion is below a fixed minimum value.

Attaching the Engine to the Cart

RateFast produces impairment ratings based on reproducible facts, rather than based on individual medical provider’s idiosyncratic interpretations of their patients’ conditions. Translating the logic of the AMA Guides into consistent workflows is achievable, but it’s a tall order—especially when applied to all possible injuries, patients, and circumstances.Although our founder’s name is Alchemy, this doesn’t just happen. It takes a lot of work.

We take feedback from our user’s, resolve logic conflicts, and look for ways to make granular details of a case usable in for workers’ compensation stakeholders.

We constantly ask ourselves how providers ask questions, how they perform exams, how they should take measurements and how measurements are actually taken (or not). We have meetings about consensus on statistical rounding, we continually consult the AMA Guides 5th edition, and we repeatedly consult one another. Josh takes this work and bridges the math with the reality—or, sometimes, the other way around.

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