Comparison with other data collection methods
(go to Outline)Some comparison of different data collection methods:
|Often collects qualitative or semi-quantitative data||Collects quantitative data||Collects quantitative data|
|Collects wide variety of data||Collects limited data||Can collect wide variety of data|
|Collects data on convenience sample of people and facilities||Often tries to collect data on every case of illness||Usually collects data on sample of population|
|Collects data at a single point in time||Collects data over ongoing, prospective time period||Collects data at single point in time|
|Collects only data for numerator of prevalence and incidence rates; Denominator must come from separate source||Collects only data for numerator of incidence and prevalence rates; Denominator must come from separate source.||Collects data for numerator and denominator, allowing calculation of prevalence or incidence rates|
As you can see, some reasons for doing surveillance cannot be met by surveys or rapid assessment; for example, collection of surveillance data can, and should, be frequent enough so that rapid decisions can be made to redirect or revise programmes quickly.