Attribution
Attribution is also called "claims based alignment" or "Claims Aligned Lives." Read on and you will find that all of these aliases point to the same purpose of the method; connecting patients to physicians using data from the claims.
Attribution is a process that CMS uses to determine a beneficiary’s primary care physician. Each program has subtle differences, but essentially, in lieu of the beneficiary telling CMS who their PCP is, CMS uses the claims data to identify the PCP. Since we have the claims data, we can follow the methodological guidelines to produce an estimate of how many patients a physician treats as a primary care physician.
These patient counts are estimates in contrast with an MSSP or DCE ACO that can actually sum all allowed charges for primary care services provided to a patient by any physician in the ACO. Since we do not have the data identifying who is in each ACO for each performance period, the CMS process that we follow identifies the physician with the majority of allowed charges for primary care services for each beneficiary. We can then count how many of those beneficiaries a physician treats.
Some important distinctions:
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MSSP ACO Attribution uses the TIN on the claim to determine which physician group the physician is billing under, because billing groups join MSSP ACOs, not usually individual physicians. Since physicians often bill under more than one group, it is common for a physician to participate in more than one MSSP ACO.
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A DCE, in contrast, is based on the individual physician and as such, 1 physician can only be in 1 DCE ACO.
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For this reason, our DCE Attribution estimates are more likely to be accurate than our MSSP Attribution estimates.
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For the first year, a physician is allowed to be in both an MSSP ACO and a DCE, but will thereafter have to choose one program or the other.
Understanding Time Periods
|
Program |
|||
|---|---|---|---|
|
MSSP ACO (Retrospective- Tracks 1 and 2) |
PY2019 |
CY2019 |
CY2019 |
|
MSSP ACO (Retrospective- Tracks 1 and 2) |
PY2020 |
CY2020 |
CY2020 |
|
DCE ACO |
Implementation Period (IP) |
Oct 1, 2020 - Mar 31, 2021 *On prod as “IP - (CY2019 Claims)” or “IP - (CY2020 Claims)” |
CY2018 (weighted 1/3) |
|
DCE ACO |
Base Year 1 (BY2017) |
CY2017 |
7/1/2014-6/30/2015 (weighted 1/3) |
|
DCE ACO |
Base Year 2 (BY2018) |
CY2018 |
7/1/2015-6/30/2016 (weighted 1/3) |
|
DCE ACO |
Base Year 3 (BY2019) |
CY2019 |
7/1/2016-6/30/2017 (weighted 1/3) |
|
DCE ACO |
Performance Year 1 (PY1) |
4/1/2021-12/31/2021 *Going into prod as “PY1 - (CY2020 Claims)” because we do not have 2021 FFS claims yet. |
7/1/2018-6/30/2019 (weighted 1/3) |
|
DCE ACO |
Performance Year 2 (PY2) |
CY2022 |
7/1/2019-6/30/2020 (weighted 1/3) |
Methodology Sources:
For those of you who want to dig in and get all of the details, please use the following links:
ACO
This methodology changes each year. The original MSSP Attributed Lives estimate used v7, PY2019 was then updated to use v8 (currently in production), PY2020 also uses v8 (data released in May, web dropdown in June), and PY2021 will be using v9.
DCE
Please download this .PDF file in the Resources section at the bottom of the article.
This original methodology only gave alignment periods for the Implementation Period and was originally run on CY2019 claims. It was updated to include historical alignment periods for Base Year 2017-2019 and Performance Years, referenced here. We also ran the same IP attribution on CY2020 claims, for comparative/trending purposes.
