PMID- 22970333
OWN - NLM
STAT- MEDLINE
DCOM- 20130128
LR  - 20211021
IS  - 1935-2735 (Electronic)
IS  - 1935-2727 (Print)
IS  - 1935-2727 (Linking)
VI  - 6
IP  - 9
DP  - 2012
TI  - Multiple category-lot quality assurance sampling: a new classification system 
      with application to schistosomiasis control.
PG  - e1806
LID - 10.1371/journal.pntd.0001806 [doi]
LID - e1806
AB  - BACKGROUND: Originally a binary classifier, Lot Quality Assurance Sampling (LQAS) 
      has proven to be a useful tool for classification of the prevalence of 
      Schistosoma mansoni into multiple categories (</=10%, >10 and <50%, >/=50%), and 
      semi-curtailed sampling has been shown to effectively reduce the number of 
      observations needed to reach a decision. To date the statistical underpinnings 
      for Multiple Category-LQAS (MC-LQAS) have not received full treatment. We explore 
      the analytical properties of MC-LQAS, and validate its use for the classification 
      of S. mansoni prevalence in multiple settings in East Africa. METHODOLOGY: We 
      outline MC-LQAS design principles and formulae for operating characteristic 
      curves. In addition, we derive the average sample number for MC-LQAS when 
      utilizing semi-curtailed sampling and introduce curtailed sampling in this 
      setting. We also assess the performance of MC-LQAS designs with maximum sample 
      sizes of n=15 and n=25 via a weighted kappa-statistic using S. mansoni data 
      collected in 388 schools from four studies in East Africa. PRINCIPLE FINDINGS: 
      Overall performance of MC-LQAS classification was high (kappa-statistic of 0.87). 
      In three of the studies, the kappa-statistic for a design with n=15 was greater 
      than 0.75. In the fourth study, where these designs performed poorly 
      (kappa-statistic less than 0.50), the majority of observations fell in regions 
      where potential error is known to be high. Employment of semi-curtailed and 
      curtailed sampling further reduced the sample size by as many as 0.5 and 3.5 
      observations per school, respectively, without increasing classification error. 
      CONCLUSION/SIGNIFICANCE: This work provides the needed analytics to understand 
      the properties of MC-LQAS for assessing the prevalance of S. mansoni and shows 
      that in most settings a sample size of 15 children provides a reliable 
      classification of schools.
FAU - Olives, Casey
AU  - Olives C
AD  - Department of Biostatistics, University of Washington, Seattle, Washington, USA.
FAU - Valadez, Joseph J
AU  - Valadez JJ
FAU - Brooker, Simon J
AU  - Brooker SJ
FAU - Pagano, Marcello
AU  - Pagano M
LA  - eng
GR  - R01 AI097015/AI/NIAID NIH HHS/United States
GR  - 1R01AI097015-01A1/AI/NIAID NIH HHS/United States
GR  - T32 ES015459/ES/NIEHS NIH HHS/United States
GR  - 092654/WT_/Wellcome Trust/United Kingdom
GR  - 098045/WT_/Wellcome Trust/United Kingdom
GR  - WT_/Wellcome Trust/United Kingdom
PT  - Evaluation Study
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, Non-U.S. Gov't
DEP - 20120906
PL  - United States
TA  - PLoS Negl Trop Dis
JT  - PLoS neglected tropical diseases
JID - 101291488
SB  - IM
MH  - Adolescent
MH  - Africa, Eastern/epidemiology
MH  - Animals
MH  - Child
MH  - Female
MH  - Humans
MH  - Lot Quality Assurance Sampling/*methods
MH  - Male
MH  - Prevalence
MH  - Schistosoma mansoni/*isolation & purification
MH  - Schistosomiasis mansoni/drug therapy/*epidemiology/*prevention & control
PMC - PMC3435238
COIS- The authors have declared that no competing interests exist.
EDAT- 2012/09/13 06:00
MHDA- 2013/01/29 06:00
PMCR- 2012/09/06
CRDT- 2012/09/13 06:00
PHST- 2012/01/03 00:00 [received]
PHST- 2012/07/17 00:00 [accepted]
PHST- 2012/09/13 06:00 [entrez]
PHST- 2012/09/13 06:00 [pubmed]
PHST- 2013/01/29 06:00 [medline]
PHST- 2012/09/06 00:00 [pmc-release]
AID - PNTD-D-12-00005 [pii]
AID - 10.1371/journal.pntd.0001806 [doi]
PST - ppublish
SO  - PLoS Negl Trop Dis. 2012;6(9):e1806. doi: 10.1371/journal.pntd.0001806. Epub 2012 
      Sep 6.