RTI International is a trade name of Research Triangle Institute

6110 Executive Blvd. ■ Suite 902 ■ Rockville, Maryland, USA 27709 Phone 301-770-8229 e-mail dcreel@rti.org

Panel Survey of Hospitals: Sampling and Estimation Challenges

Darryl V. Creel

Third International Conference on Establishment Surveys

Montreal, Quebec, Canada June 18-21, 2007

Outline

Purpose of Survey

Survey Design

Frame Development

Substitution

Estimation

Purpose of the Survey

Level of Drug Use and Abuse

Monitor Drug Use and Abuse Changes over Time

Survey Design

Complete Survey Redesign (New Beginning 2004)

Start of a New Panel – Maximize Overlap with Previous Panel

Change in Stratification Scheme Geography Ownership Size

Stratified SRS WOR of Hospitals

Review All Emergency Department Visits

Change in Case Eligibility

Annual Sample Updates to Account for New Hospitals

Change in Contractors

Survey Design

Possible Modification to the New Design Could Not Review All Emergency Department Visits in Some

Hospitals Added a Second Stage of Sampling to the New Design Select Days within Month to Review Emergency Department

Visits for Eligible Cases

Retain Single-stage Design Standard Errors – Worst Case Single-Stage SE 97% of Two-

Stage SE Computational Time – Single-Stage ~ 300 Observations

Took 12 Minutes, Two-Stage ~ 70,000 Observations Took 31.5 Hours

Frame Development

American Hospital Association (AHA) Annual Survey Database

Good Coverage

Inaccuracies in the File Incorrect FIPS Information Some for Counties in FL Nonexistant Codes

Inaccuracies in the Documentation Counts for Changes in the Population not Consistent

Only Use a Few Variables from AHA Stratification Eligibility Determination

Frame Development

Changes in Populations of Statistical Units (Struijs and Willeboordse) Change of Characteristics Change of Existence

Birth Death

Change of Structure Concentration

Merger Takeover

Deconcentration Break-Up Split-Off

Restructuring

Track for Allocation Emergency Department Visits Counts

Substitution

Hospitals are Difficult to Recruit

Use Responding Not Sampled Hospitals from the Previous Panel for Nonresponding Sampled Hospitals in Current Panel until Number of Nonresponding Hospitals in Current Panel Decreases

Substitution Only Occurs within a Sampling Stratum, i.e., Same Geography, Ownership Category, and Size Category

Match Number of Emergency Department Visits as Closely as Possible

Estimation

Main Focus on Analysis of Trends

Drug Classification Scheme Changes Constantly

Apply Most Recent Classification Scheme Retrospectively for Trends

Estimation

Actual Zero Eligible Cases

Some Hospitals Not on Micro-data Set, i.e., No Eligible Cases Found at Hospital During Charts Review

Hospitals on Micro-data Set May Not Have Specific Drugs, e.g., PCP

Carries Through to Specific Analysis

Generate Data with a Zero Value

Statistician Involvement Across All Aspects of the Survey

SUDAAN – SAMPCNT Statement

Summary

Purpose of Survey

Survey Design

Frame Development

Substitution

Estimation

Statisticians Involved