How to Investigate Drug Use in Health Facilities: Selected Drug Use Indicators - EDM Research Series No. 007: Chapter 3: Study design and sample size: Select the type of facilities for the study

How to Investigate Drug Use in Health Facilities: Selected Drug Use Indicators - EDM Research Series No. 007
(1993; 92 pages) [French] [Spanish]

Table of Contents

	Introduction
		Purpose of drug use indicators
		Objectives of a drug use study
		Background on the development of drug use indicators
		Contents of the manual
		Comments on the manual
	Chapter 1: Overview
		Types of indicators
		Types of drug use studies with indicators
		Steps in organizing and carrying out a drug use study with indicators
	Chapter 2: Core drug use indicators
		Group 1: Prescribing indicators
		Group 2: Patient care indicators
		Group 3: Health facility indicators
	Chapter 3: Study design and sample size
		Select the type of facilities for the study
		Define the types of prescribing encounters to be included
		Choose between retrospective and prospective data
		Sample size
	Chapter 4: Planning and field methods
		Personnel requirements
		Preparations for field work
		Data collection in the field
		Coding of the indicators
	Chapter 5: Analysis and reporting
		Calculating results for each facility
		Displaying the results
		Reporting results at the facility
		Reporting at the administrative level
		Results of earlier drug use studies
	Chapter 6: Follow up questions
		General directions
		Follow-up questions for specific indicators
	Annexes
		Annex 1: Sampling procedures
		Annex 2: Data collection forms
		Annex 3: Examples of earlier studies
		Annex 4: Using the indicators for monitoring
		Annex 5: Complementary drug use indicators
		Annex 6: References

Select the type of facilities for the study

The first activity of an indicators study is to select the type of health facilities to be studied, drawing randomly from a larger group of such facilities. The prescribing indicators measure aspects of outpatient treatment. They are designed for use in health centers, dispensaries or hospital outpatient departments, both public and private. In general, a single drug use study would focus on one type of facility, so that the results make sense. The prescribing indicators are less useful in inpatient settings, or in specialty outpatient clinics in referral hospitals where the drug use patterns are more complex.

Table 4. Basic parameters of different types of drug use studies

	Cross-sectional (basic)	Cross-sectional (comparative)	Supervision	Assess impact of intervention
Objective of the indicators study	To measure drug use indicators in a representative group of facilities	To compare between individual facilities or prescribers, or between groups	To identify whether a facility is above/below a set norm of practice	To assess the impact of an intervention in an intervention and a control group
# of facilities included	20	At least 10 in each group, 20 for more reliable comparisons; for individual comparisons, each facility is considered separately	Each facility sampled separately	At least 20 per group
# of prescribing encounters per facility	30	30 for comparing groups; 100 for individual facilities or prescribers	About 15 for identifying outliers with poor practices	At least 30, but depends on the need for precision
Type of prescribing data	Retrospective or prospective	Retrospective or prospective	Prospective preferred, but retrospective possible	Retrospective preferred, but depends on objectives and structure of intervention
Time frame of prescribing data	One year, if possible	One year, if possible	One day, or short period if retrospective	At least 4-6 months before and after the intervention
Type of patient care data	Prospective	Prospective	Prospective	Prospective (if necessary)