PMID- 20214765
OWN - NLM
STAT- MEDLINE
DCOM- 20100520
LR  - 20100423
IS  - 1365-3156 (Electronic)
IS  - 1360-2276 (Linking)
VI  - 15
IP  - 5
DP  - 2010 May
TI  - Clustered lot quality assurance sampling to assess immunisation coverage: 
      increasing rapidity and maintaining precision.
PG  - 540-6
LID - 10.1111/j.1365-3156.2010.02482.x [doi]
AB  - OBJECTIVE: Vaccination programmes targeting disease elimination aim to achieve 
      very high coverage levels (e.g. 95%). We calculated the precision of different 
      clustered lot quality assurance sampling (LQAS) designs in computer-simulated 
      surveys to provide local health officers in the field with preset LQAS plans to 
      simply and rapidly assess programmes with high coverage targets. METHODS: We 
      calculated sample size (N), decision value (d) and misclassification errors 
      (alpha and beta) of several LQAS plans by running 10 000 simulations. We kept the 
      upper coverage threshold (UT) at 90% or 95% and decreased the lower threshold 
      (LT) progressively by 5%. We measured the proportion of simulations with < or =d 
      individuals unvaccinated or lower if the coverage was set at the UT (pUT) to 
      calculate beta (1-pUT) and the proportion of simulations with >d unvaccinated 
      individuals if the coverage was LT% (pLT) to calculate alpha (1-pLT). We divided 
      N in clusters (between 5 and 10) and recalculated the errors hypothesising that 
      the coverage would vary in the clusters according to a binomial distribution with 
      preset standard deviations of 0.05 and 0.1 from the mean lot coverage. We 
      selected the plans fulfilling these criteria: alpha < or = 5% beta < or = 20% in 
      the unclustered design; alpha < or = 10% beta < or = 25% when the lots were 
      divided in five clusters. RESULT: When the interval between UT and LT was larger 
      than 10% (e.g. 15%), we were able to select precise LQAS plans dividing the lot 
      in five clusters with N = 50 (5 x 10) and d = 4 to evaluate programmes with 95% 
      coverage target and d = 7 to evaluate programmes with 90% target. CONCLUSION: 
      These plans will considerably increase the feasibility and the rapidity of 
      conducting the LQAS in the field.
FAU - Pezzoli, Lorenzo
AU  - Pezzoli L
AD  - Epidemiology Consultant, London, UK.
FAU - Andrews, Nick
AU  - Andrews N
FAU - Ronveaux, Olivier
AU  - Ronveaux O
LA  - eng
PT  - Journal Article
DEP - 20100308
PL  - England
TA  - Trop Med Int Health
JT  - Tropical medicine & international health : TM & IH
JID - 9610576
SB  - IM
MH  - Humans
MH  - Immunization/standards/*statistics & numerical data
MH  - Immunization Programs/*standards
MH  - Lot Quality Assurance Sampling/*standards
MH  - Models, Statistical
MH  - Program Evaluation/*standards
MH  - Quality Assurance, Health Care/*standards
MH  - Sample Size
EDAT- 2010/03/11 06:00
MHDA- 2010/05/21 06:00
CRDT- 2010/03/11 06:00
PHST- 2010/03/11 06:00 [entrez]
PHST- 2010/03/11 06:00 [pubmed]
PHST- 2010/05/21 06:00 [medline]
AID - TMI2482 [pii]
AID - 10.1111/j.1365-3156.2010.02482.x [doi]
PST - ppublish
SO  - Trop Med Int Health. 2010 May;15(5):540-6. doi: 10.1111/j.1365-3156.2010.02482.x. 
      Epub 2010 Mar 8.