Surveillance-based methods score over population survey data for the estimation of the worldwide incidence of malaria, say experts.
But they also pointed out that the present malaria surveillance systems miss at least 90 percent of cases.
Estimates of malaria incidence derived from routine surveillance data suggest that 225 million episodes of malaria occurred worldwide in 2009.
However, this estimate is lower than other published figures, such as those from the Malaria Atlas Project (MAP), particularly for estimates of malaria incidence outside Africa.
In this study, Richard Cibulskis and colleagues at the WHO in Geneva, Switzerland, produced their estimate by analysing routine surveillance reports compiled by national health ministries and conducted a statistical analysis to determine the range of uncertainty of their estimates.
The researchers also compared the strengths and weaknesses of surveillance-based and cartographic-based (relying on surveys) malaria incidence estimation methods.
They found that although at present malaria surveillance systems currently miss at least 90 percent of cases, accurate surveillance has both temporal and spatial advantages over population survey data and should therefore be the ultimate goal for malaria control programmes.
"To strengthen surveillance requires a critical evaluation of all the types of error we have identified in this paper. Only with investigations of this kind can we confidently assess malaria burden and trends, and the return on investments in control programs," the researchers said.
The study has been published in the journal PLoS Medicine.