Sampling Overview and Resources: LQAS Day3: Session 9:30-10:00pm – Jennifer Luna Operations Research Workshop February 16, 2011

LQAS  Origin in quality control for industry  light bulbs  Promoted for use in small population based health surveys  Useful for monitoring because it provides information used to identify sub-divisions (supervision areas) of project area that are underperforming  More attention can be given to these areas.  Does not provide coverage levels for supervision areas

Steps  Divide project area into supervision areas (SAs)  Decide on level below which a supervision areas is identified as priority for special attention; e.g. <85%  Randomly select sample of 19 per SA  Use a decision rule table to determine what number of correct responses is the cut off for identifying SAs that need priority attention  <20%, <1 correct response out of 19  <50%, <7 correct responses out of 19  85%, <14 correct responses out of 19 

Steps  Questions asked must be dichotomous  Was child exclusively breastfed?  Not for how many months was the child exclusively breastfed?

Supervision Area (SA)  “Lots” that you divide project area into  Should have meaning: i.e. health facility catchment areas, sub-districts or other MOH administrative areas A B C D E

Parallel Sampling  Essentially conducting multiple surveys at the same time using the same logistic system  Necessary for surveys that collect information on indicators with different age groups as denominators:  i.e. IYCF (denominator children 6-23 months);  use of ORS for diarrhea treatment (denominator children 0-23 months with diarrhea in the last two weeks)  Parallel sampling ensures that:  Each indicator will have 19 responses/supervision area

Sample Groups – CSHGP – KPC 7 Groups – Mothers of Children: months  % of children whose births were attended by skilled personnel months  % of children fed according to a minimum of appropriate feeding practices (IYCF) months  % of children who received measles vaccine months  % of children who were exclusively given breastmilk the day prior to the interview months with fever during the last 2 weeks  % treated with an effective anti-malarial months with diarrhea during the last 2 weeks  % received ORT months with cough or difficult breathing during the last 2 weeks  % taken to an appropriate health provider

LQAS – Coverage estimates  Information from supervision areas combined to obtain coverage for entire project area  LQAS with information combined from multiple SAs is a form of stratified sampling where supervision areas are strata  Weighted average of all supervision areas; confidence intervals  Total of 95 responses (5x19 = 95)  Remember parallel sampling

LQAS  Can be controversial  Not recommended for evaluative measurement of OR studies  Useful for monitoring of implementation during OR studies

Controversy - Example  Concern raised that use of LQAS to identify SAs as having reached the target, might result in mistakenly identifying an SA as one in for which resources can be reduced.  If this is a mistaken classification, then the population will not receive needed resources

ASA Recommendation Report to the American Statistical Association Board of Directors on Lot Quality Assurance Sampling, August 19, 2010 “We believe that LQAS conclusions should be carefully stated to ensure that the user will never mistakenly draw a conclusion about the performance of the SA. We propose the following as a better interpretation of the conclusions that can be drawn from LQAS: Based on considerations related to the power of the test employed, given the sample size used:

ASA recommendation continued  If 13 or more of the 19 samples of men in a supervision area (SA) can correctly name the ways to prevent sexual transmission of HIV, then we classify the SA as not requiring priority intervention at this time or  If 12 or fewer of the 19 sampled men in the SA can correctly name the ways to prevent sexual transmission of HIV, then we classify the SA as substandard requiring immediate intervention.

Articles  Rhoda, Dale A., Soledad A. Fernandez, David J. Fitch, and Stanley Lemeshow (2010), LQAS: User Beware. International Journal of Epidemiology, 39:60-68  Olives, C., M. Pagano, and J.J. Valadez (2010), Commentary: Understanding practical lot quality assurance sampling. International Journal of Epidemiology, 39:

Resources: MCHIP NGO/PVO support website  Rapid Health Surveys Handbook (Public Health Institute) CORE website: (  KPC Trainer of Survey Trainers (TOAST)  LQAS trainers guides  LQAS protocol for parallel sampling  LQAS FAQs