incidents.byCountryYr and nkill.byCountryYr are matrices giving the numbers of incidents and numbers of deaths by year and by location of the event for 206 countries (rows) and for all years between 1970 and 2016 (columns) except for 1993, for which the entries are all NA, because the raw data previously collected was lost (though the total for that year is available in the data.frame terrorism).
1. For nkill.byCountryYr and for terrorism[c('nkill', 'nkill.us')], NAs in GTD were treated as 0. Thus the actual number of deaths were likely higher, unless this was more than offset by incidents being classified as terrorism, when they should not have been.
2. incidents.byCountryYr and nkill.byCountryYr are NA for 1993, because the GTD data for that year were lost.
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year
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integer year, 1970:2016.
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methodology
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an ordered factor giving the methodology / organization responsible for the data collection for most of the given year. The Pinkerton Global Intelligence Service (PGIS) managed data collection from 1970-01-01 to 1997-12-31. The Center for Terrorism and Intelligence Studies (CETIS) managed the project from 1998-01-01 to 2008-03-31. The Institute for the Study of Violent Groups (ISVG) carried the project from 2008-04-01 to 2011-10-31. The National Consortium for the Study of Terrorism and Responses to Terrorism (START) has managed data collection since 2011-11-01. For this variable, partial years are ignored, so methodology = CEDIS for 1998:2007, ISVG for 2008:2011, and START for 2012:2014.
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method
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a character vector consisting of the first character of the levels of methodology:
c('p', 'c', 'i', 's')
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incidents
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integer number of incidents identified each year.
NOTE: sum(terrorism[["incidents"]]) = 146920 = 141966 in the GTD database plus 4954 for 1993, for which the incident-level data were lost.
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incidents.us
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integer number of incidents identified each year with country_txt = "United States".
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suicide
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integer number of incidents classified as "suicide" by GTD variable suicide = 1. For 2007, this is 359, the number reported by Pape et al. For 2013, it is 624, which is 5 more than the 619 mentioned by Pape et al. Without checking with the SMART project administrators, one might suspect that 5 more suicide incidents from 2013 were found after the data Pape et al. analyzed but before the data used for this analysis.
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suicide.us
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Number of suicide incidents by year with country_txt = "United States".
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nkill
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number of confirmed fatalities for incidents in the given year, including attackers = sum(nkill, na.rm=TRUE) in the GTD incident data.
NOTE: nkill in the GTD incident data includes both perpetrators and victims when both are available. It includes one when only one is available and is NA when neither is available. However, in most cases, we might expect that the more spectacular and lethal incidents would likely be more accurately reported. To the extent that this is true, it means that when numbers are missing, they are usually zero or small. This further suggests that the summary numbers recorded here probably represent a slight but not substantive undercount.
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nkill.us
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number of U.S. citizens who died as a result of incidents for that year = sum(nkill.us, na.rm=TRUE) in the GTD incident data.
NOTES:
1. This is subject to the same likely modest undercount discussed with nkill.)
2. These are U.S. citizens killed regardless of location. This explains at least part of the discrepancies between terrorism[, 'nkill.us'] and nkill.byCountryYr['United States', ].
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nwound
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number of people wounded. (This is subject to the same likely modest undercount discussed with nkill.)
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nwound.us
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Number of U.S. citizens wounded in terrorist incidents for that year = sum(nwound.us, na.rm=TRUE) in the GTD incident data. (This is subject to the same likely modest undercount discussed with nkill.)
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pNA.nkill, pNA.nkill.us, pNA.nwound, pNA.nwound.us
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proportion of observations by year with missing values. These numbers are higher for the early data than more recent numbers. This is particularly true for nkill.us and nwound.us, which exceed 90 percent for most of the period with methodology = 'PGIS', prior to 1998.
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worldPopulation, USpopulation
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Estimated de facto population in thousands living in the world and in the US as of 1 July of the year indicated, according to the Population Division of the Department of Economic and Social Affairs of the United Nations; see "Sources" below.
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worldDeathRate, USdeathRate
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Crude death rate (deaths per 1,000 population) worldwide and in the US, according to the World Bank; see "Sources" below. This World Bank data set includes USdeathRate for each year from 1900 to 2014.
The worldDeathRate numbers here were read manually from a plot on that web page, except for the the number for 2015, which was estimated as a reduction of 0.73 percent from 2014, which was the average rate of decline (ratio of two successive years) for 1990 to 2014. The same method was used to estimate the USdeathRate for 2015 as the same as for 2014.
NOTE: USdeathRate is to two significant digits only, unlike worldDeathRate, which has four significant digits.
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worldDeaths, USdeaths
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number of deaths by year in the world and US
worldDeaths = worldPopulation * worldDeathRate.
USdeaths were computed by summing across age groups in "Deaths_5x1.txt" for the United States, downloaded from http://www.mortality.org/cgi-bin/hmd/country.php?cntr=USA&level=1 from the Human Mortality Database; see sources below.
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kill.pmp, kill.pmp.us
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terrorism deaths per million population worldwide and in the US =
0.001 * nkill / worldPopulation
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pkill, pkill.us
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terrorism deaths as a proportion of total deaths worldwide and in the US
pkill = nkill / worldDeaths
pkill.us = nkill.us / USdeaths
If the issue is restricted to how incidents are classified as "suicide terrorism", this concern does not affect the other variables in this summary.
However, if it also impacts what incidents are classified as "terrorism", it suggests larger problems.
