Bias in epidemiological studies of conflict mortality

Neil F Johnson, Michael Spagat, Sean Gourley, Jukka Pekka Onnela, Gesine Reinert

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Cluster sampling has recently been used to estimate the mortality in various conflicts around the world. The Burnham et al. study on Iraq employs a new variant of this cluster sampling methodology. The stated methodology of Burnham et al. is to (1) select a random main street, (2) choose a random cross street to this main street, and (3) select a random household on the cross street to start the process. The authors show that this new variant of the cluster sampling methodology can introduce an unexpected, yet substantial, bias into the resulting estimates, as such streets are a natural habitat for patrols, convoys, police stations, road-blocks, cafes, and street-markets. This bias comes about because the residents of households on cross-streets to the main streets are more likely to be exposed to violence than those living further away. Here, the authors develop a mathematical model to gauge the size of the bias and use the existing evidence to propose values for the parameters that underlie the model. The research suggests that the Burnham et al. study of conflict mortality in Iraq may represent a substantial overestimate of mortality. Indeed, the recently published Iraq Family Health Survey covered virtually the same time period as the Burnham et al. study, used census-based sampling techniques, and produced a central estimate for violent deaths that was one fourth of the Burnham et al. estimate. The authors provide a sensitivity analysis to help readers to tune their own judgements on the extent of this bias by varying the parameter values. Future progress on this subject would benefit from the release of high-resolution data by the authors of the Burnham et al. study.

Original languageEnglish (US)
Pages (from-to)653-663
Number of pages11
JournalJournal of Peace Research
Volume45
Issue number5
DOIs
StatePublished - Sep 2008

Fingerprint

mortality
Iraq
trend
methodology
Sampling
habitat
census
police
road
resident
violence
death
market
Law enforcement
health
Sensitivity analysis
Gages
evidence
Values
Mathematical models

ASJC Scopus subject areas

  • Political Science and International Relations
  • Sociology and Political Science

Cite this

Johnson, N. F., Spagat, M., Gourley, S., Onnela, J. P., & Reinert, G. (2008). Bias in epidemiological studies of conflict mortality. Journal of Peace Research, 45(5), 653-663. https://doi.org/10.1177/0022343308094325

Bias in epidemiological studies of conflict mortality. / Johnson, Neil F; Spagat, Michael; Gourley, Sean; Onnela, Jukka Pekka; Reinert, Gesine.

In: Journal of Peace Research, Vol. 45, No. 5, 09.2008, p. 653-663.

Research output: Contribution to journalArticle

Johnson, NF, Spagat, M, Gourley, S, Onnela, JP & Reinert, G 2008, 'Bias in epidemiological studies of conflict mortality', Journal of Peace Research, vol. 45, no. 5, pp. 653-663. https://doi.org/10.1177/0022343308094325
Johnson NF, Spagat M, Gourley S, Onnela JP, Reinert G. Bias in epidemiological studies of conflict mortality. Journal of Peace Research. 2008 Sep;45(5):653-663. https://doi.org/10.1177/0022343308094325
Johnson, Neil F ; Spagat, Michael ; Gourley, Sean ; Onnela, Jukka Pekka ; Reinert, Gesine. / Bias in epidemiological studies of conflict mortality. In: Journal of Peace Research. 2008 ; Vol. 45, No. 5. pp. 653-663.
@article{36b16f369e1841ff981664278273c946,
title = "Bias in epidemiological studies of conflict mortality",
abstract = "Cluster sampling has recently been used to estimate the mortality in various conflicts around the world. The Burnham et al. study on Iraq employs a new variant of this cluster sampling methodology. The stated methodology of Burnham et al. is to (1) select a random main street, (2) choose a random cross street to this main street, and (3) select a random household on the cross street to start the process. The authors show that this new variant of the cluster sampling methodology can introduce an unexpected, yet substantial, bias into the resulting estimates, as such streets are a natural habitat for patrols, convoys, police stations, road-blocks, cafes, and street-markets. This bias comes about because the residents of households on cross-streets to the main streets are more likely to be exposed to violence than those living further away. Here, the authors develop a mathematical model to gauge the size of the bias and use the existing evidence to propose values for the parameters that underlie the model. The research suggests that the Burnham et al. study of conflict mortality in Iraq may represent a substantial overestimate of mortality. Indeed, the recently published Iraq Family Health Survey covered virtually the same time period as the Burnham et al. study, used census-based sampling techniques, and produced a central estimate for violent deaths that was one fourth of the Burnham et al. estimate. The authors provide a sensitivity analysis to help readers to tune their own judgements on the extent of this bias by varying the parameter values. Future progress on this subject would benefit from the release of high-resolution data by the authors of the Burnham et al. study.",
author = "Johnson, {Neil F} and Michael Spagat and Sean Gourley and Onnela, {Jukka Pekka} and Gesine Reinert",
year = "2008",
month = "9",
doi = "10.1177/0022343308094325",
language = "English (US)",
volume = "45",
pages = "653--663",
journal = "Journal of Peace Research",
issn = "0022-3433",
publisher = "SAGE Publications Ltd",
number = "5",

}

TY - JOUR

T1 - Bias in epidemiological studies of conflict mortality

AU - Johnson, Neil F

AU - Spagat, Michael

AU - Gourley, Sean

AU - Onnela, Jukka Pekka

AU - Reinert, Gesine

PY - 2008/9

Y1 - 2008/9

N2 - Cluster sampling has recently been used to estimate the mortality in various conflicts around the world. The Burnham et al. study on Iraq employs a new variant of this cluster sampling methodology. The stated methodology of Burnham et al. is to (1) select a random main street, (2) choose a random cross street to this main street, and (3) select a random household on the cross street to start the process. The authors show that this new variant of the cluster sampling methodology can introduce an unexpected, yet substantial, bias into the resulting estimates, as such streets are a natural habitat for patrols, convoys, police stations, road-blocks, cafes, and street-markets. This bias comes about because the residents of households on cross-streets to the main streets are more likely to be exposed to violence than those living further away. Here, the authors develop a mathematical model to gauge the size of the bias and use the existing evidence to propose values for the parameters that underlie the model. The research suggests that the Burnham et al. study of conflict mortality in Iraq may represent a substantial overestimate of mortality. Indeed, the recently published Iraq Family Health Survey covered virtually the same time period as the Burnham et al. study, used census-based sampling techniques, and produced a central estimate for violent deaths that was one fourth of the Burnham et al. estimate. The authors provide a sensitivity analysis to help readers to tune their own judgements on the extent of this bias by varying the parameter values. Future progress on this subject would benefit from the release of high-resolution data by the authors of the Burnham et al. study.

AB - Cluster sampling has recently been used to estimate the mortality in various conflicts around the world. The Burnham et al. study on Iraq employs a new variant of this cluster sampling methodology. The stated methodology of Burnham et al. is to (1) select a random main street, (2) choose a random cross street to this main street, and (3) select a random household on the cross street to start the process. The authors show that this new variant of the cluster sampling methodology can introduce an unexpected, yet substantial, bias into the resulting estimates, as such streets are a natural habitat for patrols, convoys, police stations, road-blocks, cafes, and street-markets. This bias comes about because the residents of households on cross-streets to the main streets are more likely to be exposed to violence than those living further away. Here, the authors develop a mathematical model to gauge the size of the bias and use the existing evidence to propose values for the parameters that underlie the model. The research suggests that the Burnham et al. study of conflict mortality in Iraq may represent a substantial overestimate of mortality. Indeed, the recently published Iraq Family Health Survey covered virtually the same time period as the Burnham et al. study, used census-based sampling techniques, and produced a central estimate for violent deaths that was one fourth of the Burnham et al. estimate. The authors provide a sensitivity analysis to help readers to tune their own judgements on the extent of this bias by varying the parameter values. Future progress on this subject would benefit from the release of high-resolution data by the authors of the Burnham et al. study.

UR - http://www.scopus.com/inward/record.url?scp=49749123502&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=49749123502&partnerID=8YFLogxK

U2 - 10.1177/0022343308094325

DO - 10.1177/0022343308094325

M3 - Article

AN - SCOPUS:49749123502

VL - 45

SP - 653

EP - 663

JO - Journal of Peace Research

JF - Journal of Peace Research

SN - 0022-3433

IS - 5

ER -