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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

Indicator

Calculation/data inputs

Data source

Indicator value

Score

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 target

140.4%

3

• Proportion of enrolled patients with SARI against set target (all eligible patients).

Number of enrolled patients with SARI / All patients with SARI.

ISS database

69.8%

2

• Proportion of SARI/ILI cases that meet the case definition

Number of ILI/SARI cases that meet the case definition / Total number of enrolled ILI/SARI cases

ISS database

86.5%

3

• Proportion of forms without at least one inconsistent or missing value for key variablesb

Number of forms without at least one incorrect or missing value / Total number of forms

ISS database

93.8%

3

• Proportion of sampled ILI/SARI cases with available laboratory results

Number of ILI/SARI cases with available laboratory results / Number of sampled ILI/SARI cases

ISS database

93.2%

3

• Proportion of sample with positive RNP results

Number of samples with a positive RNP result / Total number of samples tested

ISS database

99.8%

3

• Proportion of collected variables included in the WHO recommended minimum data collection standard

Number of collected variables within the WHO list / Number of WHO recommended variables.

CIF and WHO guidelines for influenza sentinel surveillance.

82.3%

3

Timeliness

• Proportion of samples received within the target period from collectionc

Number of samples received at the laboratory within 14 days from collection / Number of samples received

ISS database

73.2%

2

• Proportion of samples tested within one week from receipt

Number of samples tested within two weeks from receipt / Number of samples tested

ISS database

87.3%

3

Representativeness

• Geographical coverage

Number of provinces covered by the influenza sentinel surveillance network / Total number of provinces of the country

Geographic distribution of sentinel sites.

20.0%

1

• Inclusion of all age groups

Age distribution of ILI/SARI cases (median, minimum and maximum)

ISS database

Med.: 4 Y

3

Min.: 0 Y

Max.: 97 Y

Flexibility

• Expansion of sentinel sites participating to the ISSS since inception

Number of new sentinel sites since inception

Protocol

5

3

• Surveillance for pathogens other than influenza

Number of investigated pathogens other than influenza

Protocol

10

3

  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