Menu ENN Search

Field testing LQAS to assess acute malnutrition prevalence

Summary of published research1

In emergency settings, the prevalence of global acute malnutrition (GAM) needs to be assessed quickly, accurately and often repeatedly, to determine when and where to start and stop humanitarian aid. The most common approach for assessing GAM is a two-stage 30 x 30 cluster survey - which can be time-consuming and expensive. Alternative, less time-consuming and resource-intensive approaches are needed. One of the most frequently used quality control statistical methods in international health is Lots Quality Assurance Sampling (LQAS). Cumulative binomial probabilities are used in LQAS analyses to detect if a critical threshold has been reached for an indicator. To design an LQA sampling plan, the threshold of interest for an indicator, e.g. GAM prevalence, and tolerable statistical error are defined a priori.

A recently published article examines three adaptations of LQAS to assess GAM and other child-level indicators in food-insecure settings.

Computer simulations confirmed that small clusters instead of a simple random sample could be used for LQAS assessments of GAM. Three LQAS designs were developed (33 x 6, 67 x 3, sequential design)2,3, to assess GAM thresholds of 10, 15 and 20%. The designs were field-tested simultaneously with a 30 x 30 cluster-survey in Siraro, Ethiopia during June 2003. Using a nested study design, anthropometric, morbidity and vaccination data were collected on all children 6-59 months in sampled households. Hypothesis tests about GAM thresholds were conducted for each LQAS design. Point estimates were obtained for the 30 x 30 cluster-survey and the 33 x 6 and 67 x 3 LQAS designs. In order to collect data for the study, 15 interviewers were hired and trained. Teams used an odometer to record the distance travelled from the base camp to the first cluster for each work-day and used a stopwatch to record the time required to complete each survey.

Hypothesis tests showed GAM as < 10% for the 33 x 6 design and GAM as > or = 10% for the 67 x 3 and sequential designs. Point estimates for the 33 x 6 and 67 x 3 designs were similar to those of the 30 x 30 cluster-survey for GAM (6.7%, Confidence Interval (CI) = 3.2-10.2%; 8.2%, CI= 4.3-12.1%, 7.4%, CI - 4.8-9.9%, respectively) and all other indicators. The CIs for the LQAS designs were only slightly wider than the CIs for the 30 x 30 cluster-survey, yet the LQAS designs required substantially less time to administer.

The study concluded that the LQAS designs provide statistically appropriate alternatives to the more timeconsuming 30 x 30 cluster-survey. However, additional field-testing is needed using independent samples rather than a nested study design, which was the most critical limitation of the study. Ideally, data for each design should be sampled independently to allow for stricter comparison of results between designs.

Despite this limitation, the authors concluded that LQAS designs can contribute to the methodological toolkit of humanitarian agencies.

 

Show footnotes

1Deitchler M et al (2007). A field test of three LQAS designs to assess the prevalence of acute malnutrition. Int J. Epidemiology. Advance access published May 21st, 2007, pp 1-7. The article is available free from http://ije.oxfordjournals.org/cgi/content/abstract/dym092v1

2Thirty-three clusters with six children in each, sixty seven clusters with three children in each, etc.

3A Retrospective Study of Emergency Supplementary Feeding Programmes. Dr Carlos Navarro-Colarado. June 2007. ENN and SC UK. Available at http://www.ennonline.net/research/

More like this

FEX: Piloting LQAS in Somaliland

By Tom Oguta, Grainne Moloney and Louise Masese Tom Oguta has been working with FAO/FSAU in the Nutrition Surveillance Project in Somalia as a Nutrition Project Officer for...

en-net: Cluster Designs to Assess the Prevalence of Acute Malnutrition by Lot Quality Assurance Sampling: A Validation Study by Computer Simulation

The Food and Nutrition Technical Assistance Project II (FANTA-2) would like to announce the release of "Cluster Designs to Assess the Prevalence of Acute Malnutrition by Lot...

en-net: Any robust experiences using LQAS for assessing and monitoring nutrition programs using Valadez's common health survey method?

I have searched the ENN forum and followed past LQAS survey discussions on this site; however, as a health person, I am wondering why I have not been able to find widespread...

en-net: Quick and (not) dirty

What would be the most adequate and practical rapid nutrition assessment tool to be carried out in a huge emergency e.g. Pakistan floods if circumstances and time do not allow...

en-net: LQAS types

I have a chance to read number of assessment reports using LQAS but they used different terminologies/methods regarding LQAS. these are the conventional LQAS, cluster LQAS and...

FEX: Comparison of LQAS and 30-by-30 two-stage cluster sampled survey method for the assessment of coverage indicators

By Asrat Dibaba, Charles Chimombo, Ari Uotila, Whitney King and Mark Myatt Asrat Dibaba is the Maternal, Newborn and Child Health Advisor for World Vision East Africa Region...

en-net: Is it possible to use LQAS methodology to assess the prevalence of stunting in non-emergency settings?

We are wanting to assess the prevalence of stunting in a non-emergency setting. Only stunting (height and age) and no other variables. Does anyone know if it is possible to...

FEX: Alternative Sampling Designs for Emergency Settings

The Food and Nutrition Technical Assistance II Project (FANTA-2) has recently released new guidance material on survey sampling in emergencies. 'Alternative Sampling Designs...

FEX: Interpreting results of field surveys using probability calculators

By Oleg O Bilukha and Curtis Blanton Dr. Oleg Bilukha is a Medical Epidemiologist with the International Emergency and Refugee Health Branch (IERHB), Centers for Disease...

en-net: Sample size for IYCF assessment

We are on process to conduct baseline nutrition survey (two stage cluster sampling, 30 by 30). Within this survey, we want to include assessment of IYCF for children 0 to 23...

en-net: WHO EPI two stage cluster survey method Vis-à-vis DHS or MICS approach

We are planing to conduct nutrition assessment which includes anthropometry, feeding practices, morbidity, hygiene and sanitation, EPI, vit A supp and other relevant areas. The...

en-net: Stratified cluster survey with 5 stratum Vs. 5 independant surveys

I need to get GAM estimates for a state and 5 counties within the state in South Sudan. I am planning to conduct 5 independent surveys (1 per county) and combine the results...

en-net: DESIGN EFFECT FOR MULTIPLE SMART SURVEY

I need guidance on how to get a single design effect for three separate surveys done last year at Sub-county level. We need to conduct a SMART survey at County level and...

en-net: Nutrition assessment in small pieces livelihood zones

Unfortunately, our nutrition program fall under three livelihood area. The total program catchment population is about 120,000. The proportion of population in the three...

en-net: Sample size determination

Hi there,
I am planning a nutrition survey in an area where previous estimates indicated 45% stunting prevalence. I would like to cover the entire district so I am not...

FEX: The Pakistan Earthquake Survey: Methodological Lessons Learned

By Leah Richardson, Moazzem Hossain and Kevin Sullivan Acknowledgements go out to the survey teams as well as to those responsible for the close partnership between UNICEF,...

en-net: Sample size calculation on IYCF indicators in small scale survey

Dear Practitioners We are planning to conduct a baseline survey which is aimed to capture information for malnutrition and IYCF but also hygiene, other micronutrient...

en-net: % of Stunting prevelence or Mean WHZ score

Hi, We are developing one programme one nutrition sensitive social protection programme on maternity cash transfer with intensive behaviour change communication. Below were...

FEX: IYCF assessment with small-sample surveys - A proposal for a simplified and structured approach

By Ernest Guevarra (VALID International), Katja Siling (VALID International), Faraja Chiwile (UNICEF Sierra Leone), Mueni Mutunga (UNICEF Sierra Leone UNICEF Sudan), Joseph...

en-net: S3M

In looking at materials on CSAS, there are several references to S3M but I can't find anything that actually explains it. Does anyone have any resources for that? Hi Mark, I...

Close

Reference this page

Field testing LQAS to assess acute malnutrition prevalence. Field Exchange 31, September 2007. p4. www.ennonline.net/fex/31/fieldtestinglqas