Impact Variables

What Type of Information Is Collected to Evaluate the Impact of a Disaster? How Is It Aggregated, Reported, or Adjusted?

1: Human Impact Variables
2: Economic Impact Variables

1 - Human Impact Variables

People Affected and Death Toll

Five variables describe the human impact of disasters in the EM-DAT Public Table:

Human Impact Variables

Total Deaths, which includes reported deaths and missing people,
No. Injured,
No. Affected,
No. Homeless, and
Total Affected, which is the sum of No. Injured, No. Affected, and No. Homeless.

The reported total number of deaths (column Total Deaths) includes confirmed fatalities directly imputed to the disaster plus missing people whose whereabouts since the disaster are unknown and so they are presumed dead based on official figures.

Aside from fatalities, the number of injured people (column No. Injured) is entered when the term “injured” is written in the source. Any related word like “hospitalized” is considered as injured. If no precise number is given, such as “hundreds of injured,” 200 injured will be entered (although this figure is probably an underestimate).

The number of affected people (column No. Affected) is often mentioned and is widely used by different actors to convey the extent, impact, or severity of a disaster in non-spatial terms. If only the number of families affected or houses damaged are reported, the figure is multiplied by the average family size for the affected area (×5 for developing countries, ×3 for industrialized countries, according to the UNDP country classification).

Calculation of `No. Affected` (Examples)

Number of houses damaged: 50 × 5 = 250 affected (although this figure is probably an underestimate).
If the value ranges from a minimum to a maximum: the average is taken.
Thousands affected: 2,000 affected (although this figure is probably an underestimate).

Similarly, the indicator No. Homeless is mentioned whenever it is found in reports. If only the number of families that are homeless or houses that are destroyed are reported, the figure is multiplied by the average family size for the affected area (x5 for developing countries, x3 for industrialized countries, according to the UNDP country list).

Calculation of `No. Homeless` (Examples)

Number of houses destroyed: 50 × 5 = 250 homeless (although this figure is probably an underestimate).
If the value ranges from a minimum to a maximum: take the average.
Thousands homeless: 2,000 homeless (although this figure is probably an underestimate).

Finally, the indicator Total Affected is the total of injured, affected, and homeless people. For each disaster and its corresponding sources, the population referred to in these statistics and the apportionment between injured, affected, homeless, and the total is carefully checked by CRED staff members.

Human Impact and Conceptual Uncertainties

The terms “dead,” “injured,” and “homeless” are more straightforward than “affected persons.” The definition of “affected persons” varies across sources and lacks a universal standard. Besides, for disasters such as droughts or heatwaves, which have ambiguous spatiotemporal boundaries, determining the number of casualties can be challenging. CRED directly uses numbers in EM-DAT as they appear in original sources, even if there are uncertainties in these figures. More details on these uncertainties can be found in the section on General Issues.

Usually, at least the field Total Deaths or Total Affected are found in EM-DAT records as these numbers are involved as entry criteria. However, records often contain incomplete impact statistics (see Accounting Biases).

2 - Economic Impact Variables

Total Economic Damage, Reconstruction Costs, and Insured Damage

Six variables describe the economic impact of disasters in the EM-DAT Public Table:

Economic Impact Variables

Reconstruction Costs ('000 US$),
Reconstruction Costs, Adjusted ('000 US$),
Insured Damage ('000 US$),
Insured Damage, Adjusted ('000 US$),
Total Damage ('000 US$), and
Total Damage, Adjusted ('000 US$).

These six statistics are the three same statistics (Reconstruction Costs ('000 US$), Insured Damage ('000 US$), and Total Damage ('000 US$)) repeated to also provide an amount corrected for inflation, i.e., “Adjusted” (See Economic Adjustment). Damage and costs are converted and expressed in thousands of US dollars (‘000 US$).

Underreporting of Economic Losses

Economic damage resulting from disasters is largely underreported. In EM-DAT, figures tend to be available only for high-impact disasters in countries with insurance and reinsurance coverage. This issue is described in the Specific Biases section, in particular, in the Accounting Biases section.

Reconstruction costs are different from total damages as they must consider the current construction or purchase costs of goods, as well as the additional cost of prevention and mitigation measures designed to reduce damage from future disasters. Hence, when reconstruction costs are specified, they are usually greater than the total damage.

Insured damage is usually reported by reinsurance companies that publish figures about disaster losses, e.g., MunichRe, SwissRe, or AON. When insured damage is reported, the total damage is generally reported from the same source for consistency.