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Table 2 Indicators for data quality and completeness, timeliness, representativeness and flexibility used for the evaluation of the influenza sentinel surveillance system in Zambia, 2011-2017a

From: An evaluation of the Zambia influenza sentinel surveillance system, 2011–2017

IndicatorCalculation/data inputsData sourceIndicator valueScore
Data quality and completeness
• Proportion of enrolled patients with ILI against set target (5 patients per week per site).Number of enrolled patients with ILI / Estimated target.ISS database and estimated target140.4%3
• Proportion of enrolled patients with SARI against set target (all eligible patients).Number of enrolled patients with SARI / All patients with SARI.ISS database69.8%2
• Proportion of SARI/ILI cases that meet the case definitionNumber of ILI/SARI cases that meet the case definition / Total number of enrolled ILI/SARI casesISS database86.5%3
• Proportion of forms without at least one inconsistent or missing value for key variablesbNumber of forms without at least one incorrect or missing value / Total number of formsISS database93.8%3
• Proportion of sampled ILI/SARI cases with available laboratory resultsNumber of ILI/SARI cases with available laboratory results / Number of sampled ILI/SARI casesISS database93.2%3
• Proportion of sample with positive RNP resultsNumber of samples with a positive RNP result / Total number of samples testedISS database99.8%3
• Proportion of collected variables included in the WHO recommended minimum data collection standardNumber of collected variables within the WHO list / Number of WHO recommended variables.CIF and WHO guidelines for influenza sentinel surveillance.82.3%3
• Proportion of samples received within the target period from collectioncNumber of samples received at the laboratory within 14 days from collection / Number of samples receivedISS database73.2%2
• Proportion of samples tested within one week from receiptNumber of samples tested within two weeks from receipt / Number of samples testedISS database87.3%3
• Geographical coverageNumber of provinces covered by the influenza sentinel surveillance network / Total number of provinces of the countryGeographic distribution of sentinel sites.20.0%1
• Inclusion of all age groupsAge distribution of ILI/SARI cases (median, minimum and maximum)ISS databaseMed.: 4 Y3
Min.: 0 Y
Max.: 97 Y
• Expansion of sentinel sites participating to the ISSS since inceptionNumber of new sentinel sites since inceptionProtocol53
• Surveillance for pathogens other than influenzaNumber of investigated pathogens other than influenzaProtocol103
  1. Abbreviations: ILI influenza-like-illness; SARI severe acute respiratory illness; CIF case investigation form; RNP RiboNucleic Protein; WHO World Health Organization; ISS influenza sentinel surveillance
  2. aEach quantitative indicator was evaluated as the proportion (expressed as percentage) of the outcome of interest over the total (indicator value). A scale from 1 to 3 was used to provide a score for each quantitative indicator as follows: < 60% (from the above calculation) scored 1 (weak performance); 60–79% scored 2 (moderate performance); ≥80% scored 3 (good performance)
  3. bKey variables evaluated for completeness and consistency of data: site, age/date of birth, sex, date of consultation/admission, date of symptoms onset, date of sample collection and signs and symptoms included in the case definitions
  4. cThe target period was 48 h from sites situated in Lusaka Province and 14 days from sites situated in Copperbelt Province