PMID- 10128376
OWN - NLM
STAT- MEDLINE
DCOM- 19931020
LR  - 20190513
IS  - 0268-1080 (Print)
IS  - 0268-1080 (Linking)
VI  - 8
IP  - 3
DP  - 1993 Sep
TI  - Lot quality assurance sampling for monitoring immunization programmes: 
      cost-efficient or quick and dirty?
PG  - 217-23
AB  - In recent years Lot quality assurance sampling (LQAS), a method derived from 
      production-line industry, has been advocated as an efficient means to evaluate 
      the coverage rates achieved by child immunization programmes. This paper examines 
      the assumptions on which LQAS is based and the effect that these assumptions have 
      on its utility as a management tool. It shows that the attractively low sample 
      sizes used in LQAS are achieved at the expense of specificity unless unrealistic 
      assumptions are made about the distribution of coverage rates amongst the 
      immunization programmes to which the method is applied. Although it is a very 
      sensitive test and its negative predictive value is probably high in most 
      settings, its specificity and positive predictive value are likely to be low. The 
      implications of these strengths and weaknesses with regard to management 
      decision-making are discussed.
FAU - Sandiford, P
AU  - Sandiford P
AD  - International Health Division, Liverpool School of Tropical Medicine, UK.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - Health Policy Plan
JT  - Health policy and planning
JID - 8610614
MH  - Child
MH  - Child Health Services/*standards/statistics & numerical data
MH  - Cost-Benefit Analysis
MH  - Data Collection
MH  - Decision Making, Organizational
MH  - England
MH  - Humans
MH  - Immunization/*standards/statistics & numerical data
MH  - Infant
MH  - Measles/immunology
MH  - Models, Statistical
MH  - Program Evaluation/*methods
MH  - Quality Assurance, Health Care/*methods
MH  - Sampling Studies
OID - PIP: 090182
OID - POP: 00226673
OAB - The production line industry uses lot quality assurance sampling (LQAS) to 
      categorize the quality of batches of a product as either permissible or 
      unsatisfactory based on the proportion of defective units in each found by 
      inspecting a sample of units. LQAS may be a method to assess coverage rates 
      achieved by child immunization. The proportion of appropriately-aged children an 
      immunization program is responsible for would be the batches. Defective units 
      would include children not fully immunized and beyond the age of immunization. An 
      international health specialist uses UNICEF country estimates for measles 
      vaccination (1991), assuming good performance to be 80% coverage (i.e.g, 20% 
      defectives) and poor performance to be 50% coverage, to demonstrate the strengths 
      and limitations of the LQAS method. This exercise reveals that this test is very 
      good at detecting poor performance. Its sensitivity is almost 99%, and its 
      community risk is less than 2%. Its negative predictive value tends to be high in 
      most settings. The LQAS test also does a good job at making sure that programs 
      which do well are not rejected. On the other hand, the LQAS method is not very 
      specific, and its positive predictive value tends to be low in most settings. For 
      example, it rejected 25-30% (false positive rate) of countries with coverage 
      rates above 50%. Thus, the LQAS method is not necessarily good at predicting when 
      a program is doing a good job. These findings illustrate the importance of 
      program managers and planners recognizing the strengths and weaknesses of LQAS 
      before using it to evaluate their immunization program.
OABL- eng
OTO - PIP
OT  - Behavior
OT  - *Decision Making
OT  - Delivery Of Health Care
OT  - *Developed Countries
OT  - *Developing Countries
OT  - Diseases
OT  - Error Sources
OT  - Evaluation
OT  - *Evaluation Methodology
OT  - *False Positive Reactions
OT  - Health
OT  - Health Services
OT  - *Immunization
OT  - *Measles
OT  - Measurement
OT  - *Methodological Studies
OT  - *Organization And Administration
OT  - Primary Health Care
OT  - *Quality Control
OT  - Research Methodology
OT  - *Testing
OT  - Viral Diseases
GN  - PIP: TJ: HEALTH POLICY AND PLANNING.
EDAT- 1993/08/06 00:00
MHDA- 1993/08/06 00:01
CRDT- 1993/08/06 00:00
PHST- 1993/08/06 00:00 [pubmed]
PHST- 1993/08/06 00:01 [medline]
PHST- 1993/08/06 00:00 [entrez]
AID - 10.1093/heapol/8.3.217 [doi]
PST - ppublish
SO  - Health Policy Plan. 1993 Sep;8(3):217-23. doi: 10.1093/heapol/8.3.217.