World Disasters Report 2010 - International Federation of Red Cross ...

ANNEX 1
164
Caveats
Key problems with disaster data include the lack of standardized collection methodologies
and definitions. The original information, collected from a variety of public
sources, is not specifically gathered for statistical purposes. So, even when the compilation
applies strict definitions for disaster events and parameters, the original suppliers
of information may not. Moreover, data are not always complete for each disaster. The
quality of completion may vary according to the type of disaster (for example, the
number of people affected by transport accidents is rarely reported) or its country of
occurrence.
Data on deaths are usually available because they are an immediate proxy for the severity
of the disaster. However, the numbers put forward immediately after a disaster may
sometimes be seriously revised, occasionally several months later.
Data on the number of people affected by a disaster can provide some of the most
potentially useful figures, for planning both disaster preparedness and response, but
they are sometimes poorly reported. Moreover, the definition of people affected
remains open to interpretation, political or otherwise. Even in the absence of manipulation,
data may be extrapolated from old census information, with assumptions being
made about percentages of an area’s population affected.
Data can also be skewed because of the rationale behind data gathering. Reinsurance
companies, for instance, systematically gather data on disaster occurrence in order to
assess insurance risk, but with a priority in areas of the world where disaster insurance
is widespread. Their data may therefore miss out poor, disaster-affected regions where
insurance is unaffordable or unavailable.
For natural disasters over the last decade, data on deaths are missing for around onetenth
of reported disasters; data on people affected are missing for around one-fifth
of disasters; and data on economic damages are missing for 67 per cent of disasters.
The figures should therefore be regarded as indicative. Relative changes and trends are
more useful to look at than absolute, isolated figures.
Dates can be a source of ambiguity. For example, a declared date for a famine is both
necessary and meaningless – a famine does not occur on a single day. In such cases,
the date the appropriate body declares an official emergency has been used. Changes
in national boundaries cause ambiguities in the data and may make long-term trend
analysis more complicated.
However, in some cases, available data may differ greatly according to sources, be more
or less documented estimations and / or subject to controversies. In these cases, CRED
always compiles all available data or analysis to try to make its own documented estimation,
which can be revised when more accurate data are provided.