Alternative Approaches to Approximate an Analytic Sample

Purpose

This module provides an in depth description of alternative approaches to approximate an analytic sample size of NHANES participants who linked to the CMS data file.

Task 1: Locate the Match Rate Tables for NHANES-CMS Linked Data

This task will provide information on the location of the NHANES-CMS linked data match rate tables. The match rate tables are provided for researchers wanting an estimate of sample sizes.

Information regarding the number and percentage of NHANES participants who were linked to the Medicare Enrollment Database (EDB) and/or Medicaid Person Summary File during the linkage period are provided. This task will provide information on the location of the NHANES-CMS linked data match rate tables.

Go to the Data Linkage page on the NCHS website.
On the left navigation menu, expand CMS Medicare Data, and click on Linkage Methods/Analytic Support.
Click the Match Rate Table for NCHS-CMS Medicare Files link.
The PDF file opens to the table. It displays the sample size and unweighted linkage rates for each NCHS survey linked to Medicare enrollment data.
Scroll down to the third page of the document and find rows containing data for NHANES.
The first column, labeled “Total Sample,” contains the total sample sizes for each NHANES cycle.
The third column, labeled “Linked to Medicare Administrative Data,” contains the number of NHANES participants who were linked to the EDB during the linkage period.

Go to the Data Linkage page on the NCHS website.
On the left navigation menu, expand CMS Medicaid Data, and click on Linkage Methods/Analytic Support.
Click the Match Rate Table for NCHS-CMS Medicaid Files link.
The PDF file opens to the table. It displays the sample size and unweighted linkage rates for each NCHS survey linked to Medicaid enrollment data.
Scroll down to the fifth page of the document and find rows containing data for NHANES.
The first column, labeled “Total Sample,” contains the total sample sizes for each NHANES cycle.
The third column, labeled “Linked to Medicaid Data” contains the number of NHANES participants who were linked to the Medicaid Analytic eXtract (MAX) Person Summary File during the linkage period.

Task 2: Locate the Sample Count Tables to Approximate an Analytic Sample Size

The sample count tables are another resource that can be used to estimate potential sample sizes by providing the number of NHANES participants in each CMS file. This task will show you how to calculate an approximate analytic sample size for your research.

Sample count tables for providing the number of records on each specific CMS enrollment and claims files are available. This task will provide information on how to locate and approximate an analytic sample using the NHANES-CMS linked data sample count tables. The sample counts information is provided for researchers wanting an estimate of sample sizes by enrollment year and claims file type.

Go to the Data Linkage page on the NCHS website.
On the left navigation menu, expand CMS Medicare Data, and click on Linkage Methods/Analytic Support.
Click the Sample Sizes for Restricted-Use NCHS-CMS Medicare Files link.
The PDF file of the table opens to the table. It displays the number of NCHS participants with records on each Medicare enrollment and claims files by survey and year.
Note that the numbers in the table described in Task 1 may differ from those provided in this table because the preceding table provides counts of NHANES participants who were linkage-eligible and successfully linked to the Medicare Enrollment Database (EDB) during the linkage period, whereas the table described in this task provides the number of records for NHANES participants in each Medicare enrollment or claims file by year.
Scroll down to the NHANES data, beginning on page 12.
The second column, labeled “Master Beneficiary Summary File,” contains the yearly record counts which are the largest potential sample of linked NHANES participants for a given year
Additional columns in the data table show the number of claims records available for NHANES participants by claim type (e.g., Carrier, MedPAR) and year.

Go to the Data Linkage page on the NCHS website.
On the left navigation menu, expand CMS Medicaid Data, and click on Linkage Methods/Analytic Support.
Click the Sample Sizes for Restricted-Use NCHS-CMS Medicaid Files link.
The PDF file of the table opens and displays the number of NCHS participants with records on each of the Medicaid Analytic eXtract (MAX) files by survey and year.
Note that the numbers in the table described in Task 1 may differ from those provided in this table because the preceding table provides counts of NHANES participants who were linkage-eligible and successfully linked to the MAX Person Summary File during the linkage period, whereas the table described in this task provides the number of records for NHANES participants in each MAX file by year.
Scroll down to the pages containing NHANES data, beginning on page 12.
The second column, labeled “Person Summary (PS) File,” contains the yearly Person Summary File record counts which are the largest potential sample of linked NHANES participants for a given year.
Additional columns in the data table show the number of records available for NHANES participants by claim type (e.g., Inpatient Hospital (IP) File, Long-Term (LT) Care File) and year.

Task 3: Locate the Managed Care Enrollment Table for NHANES-CMS Linked Data

When estimating sample sizes for analyses involving CMS claims data, it is important to consider the NHANES-CMS linked participants enrolled in Medicare Advantage (MA) and/or Medicaid managed care plans. MA, also referred to as Medicare Part C, includes Health Maintenance Organizations (HMOs), Managed Care Plans, Preferred Provider Organizations (PPOs), Private Fee-for-Service (PFFS) Plans, Special Needs Plans, and Medicare Medical Savings Account Plans. Until recently, CMS generally did not receive claims data for Medicare beneficiaries who enrolled in MA plans. For enrollees in Medicaid managed care plans, information in the Medicaid Analytic eXtract (MAX) files are limited and the availability varies by state. This task identifies NCHS resources that will enable you approximate the number of beneficiaries enrolled in a MA and Medicaid managed care plan.

If your research project includes analyzing claims data, you should take into consideration the number of MA or Medicaid managed care plan enrollees that are included in your estimated sample sizes calculated in Task 2. This task will provide information on how to locate the table to estimate the number of NHANES-CMS linked participants enrolled in MA and Medicaid managed care plans.

Go to the Data Linkage page on the NCHS website.
On the left navigation menu, expand CMS Medicare Data, and click on Linkage Methods/Analytic Support.
Click the Medicare Advantage enrollment table for NCHS-CMS Medicare Files link.
The PDF file of the table opens to the table. It displays the percentage of NCHS survey participants enrolled in MA by survey, age group, and year of Medicare enrollment.
Scroll down to page 4 containing NHANES data.
The table provides the percentage of linked NHANES participants enrolled in MA for each Medicare enrollment year. The percentages are provided for each survey overall and by age category (less than 65 years of age/65 years of age and older).

Go to the Data Linkage page on the NCHS website.
On the left navigation menu, expand CMS Medicaid Data, and click on Linkage Methods/Analytic Support.
Click the Medicaid Managed Care Program Enrollment Table for NCHS-CMS Medicaid Files link.
The PDF file of the table opens to the table. It displays the percentage of NCHS survey participants enrolled in a Medicaid Comprehensive Managed Care Program for each MAX data year. The percentages are provided by year for each NCHS survey linked to Medicaid data.

Page last reviewed: October 29, 2020

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