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BMJ. 2002 February 9; 324(7333): 342–345.
PMCID: PMC1122271

Root causes of violent conflict in developing countries

Frances Stewart, director

Poverty and political, social, and economic inequalities between groups predispose to conflict; policies to tackle them will reduce this risk

Eight out of 10 of the world's poorest countries are suffering, or have recently suffered, from large scale violent conflict. Wars in developing countries have heavy human, economic, and social costs and are a major cause of poverty and underdevelopment. The extra infant deaths caused by the war in Cambodia, for example, were estimated to be 3% of the country's 1990 population.1 Most current conflicts, such as in the Sudan or the Congo, are within states, although there is often considerable outside intervention, as in Afghanistan. In the past 30 years Africa has been especially badly affected by war (see fig fig11).

Figure 1
Number of armed conflicts by level, 1946–2000. (Adapted from Gleditsch NP, Wallensteen P, Eriksson M, Sollenberg M, Strand H. Armed conflict 1946-2000: a new dataset.

This article reviews the evidence on the root causes of conflict and suggests some policy responses that should be adopted to reduce the likelihood of future war.

Summary points

  • Wars are a major cause of poverty, underdevelopment, and ill health in poor countries
  • The incidence of war has been rising since 1950, with most wars being within states
  • Wars often have cultural dimensions related to ethnicity or religion, but there are invariably underlying economic causes too
  • Major root causes include political, economic, and social inequalities; extreme poverty; economic stagnation; poor government services; high unemployment; environmental degradation; and individual (economic) incentives to fight
  • To reduce the likelihood of wars it is essential to promote inclusive development; reduce inequalities between groups; tackle unemployment; and, via national and international control over illicit trade, reduce private incentives to fight

The cultural dimension of war

Many groups of people who fight together perceive themselves as belonging to a common culture (ethnic or religious), and part of the reason that they are fighting may be to maintain their cultural autonomy. For this reason, there is a tendency to attribute wars to “primordial” ethnic passions, which makes them seem intractable. This view is not correct, however, and diverts attention from important underlying economic and political factors.

Although a person's culture is partly inherited it is also constructed and chosen, and many people have multiple identities.2 Many of the ethnic identities in Africa that today seem to be so strong were “invented” by the colonial powers for administrative purposes and have only weak origins in precolonial Africa.3 Their boundaries are generally fluid, and they have rightly been described as “fuzzy sets.”4

In wars political leaders may deliberately “rework historical memories” to engender or strengthen this identity in the competition for power and resources. For example, in the conflict in Matebeland in post-independence Zimbabwe, Ndebele identity was used to advance political objectives.5 Other well known examples include the Nazis in Germany, the Hutus in Rwanda (fig (fig2),2), and, today, the emphasis on Muslim consciousness by the Taliban and others.

Figure 2
 Victims of a massacre by Hutus in Rwanda

Economic factors which predispose to war

Four economic hypotheses have been put forward to explain intra-state wars, based on factors related to group motivation, private motivation, failure of the social contract, and environmental degradation.

Group motivation hypothesis—Since intra-state wars mainly consist of fighting between groups, group motives, resentments, and ambitions provide motivation for war.4,6,7 Groups may be divided along cultural or religious lines, by geography, or by class. Group differences only become worth fighting for, however, if there are other important differences between groups, particularly in the distribution and exercise of political and economic power.8 In this situation relatively deprived groups are likely to seek (or be persuaded by their leaders to seek) redress. Where political redress is not possible they may resort to war. Resentments inspired by group differences, termed horizontal inequalities, are a major cause of war. These group differences have many dimensions—economic, political, and social (see table ). Relatively privileged groups may also be motivated to fight to protect their privileges against attack from relatively deprived groups.6

Private motivation hypothesis—War confers benefits on individuals as well as costs which can motivate people to fight.9,10 Young uneducated men, in particular, may gain employment as soldiers. War also generates opportunities to loot, profiteer from shortages and from aid, trade arms, and carry out illicit production and trade in drugs, diamonds, timber, and other commodities. Where alternative opportunities are few, because of low incomes and poor employment, and the possibilities of enrichment by war are considerable, the incidence and duration of wars are likely to be greater. This “greed hypothesis” has its base in rational choice economics.10,11

Failure of the social contract—This derives from the view that social stability is based on a hypothetical social contract between the people and the government. People accept state authority so long as the state delivers services and provides reasonable economic conditions (employment and incomes). With economic stagnation or decline, and worsening state services, the social contract breaks down, and violence results. Hence high and rising levels of poverty and a decline in state services would be expected to cause conflict.12

Green war hypothesis—This points to environmental degradation as a source of poverty and cause of conflict.13,14 For example, rising population pressure and falling agricultural productivity may lead to land disputes. Growing scarcity of water may provoke conflict.15 This hypothesis contradicts the view that people fight to secure control over environmental riches.10,16

The four hypotheses are not mutually exclusive. For example, the conflict in the Sudan is an example of both horizontal inequality (with people in the south being heavily deprived) and powerful private gains that perpetuate the struggle.9 While environmental poverty has plausibly been an important factor in the conflict in Rwanda, it does not seem to have been in the former Yugoslavia.

The evidence underpinning the hypotheses

Evidence from case studies and statistical analyses suggest that each hypothesis has something to contribute to explaining conflict.

Group inequality—There is consistent evidence of sharp horizontal inequalities between groups in conflict.17 Group inequalities in political access are invariably observed—hence the resort to violence rather than seeking to resolve differences through political negotiation. Group inequalities in economic dimensions are common, although not invariably large (such as in Bosnia18). Horizontal inequalities are most likely to lead to conflict where they are substantial, consistent, and increasing over time. Although systematic cross country evidence is rare, one study classified 233 politicised communal groups in 93 countries according to political, economic, and ecological differences and found that most groups suffering horizontal inequalities had taken some action to assert group interests, ranging from non-violent protest to rebellion.4

Private motivation—The view that private motivation plays an important role in prolonging, if not causing, conflict in some countries is well supported by work in the Sudan, Sierra Leone, and Liberia.9,19,20 Collier and Hoeffler tested the greed hypothesis (albeit with a rather crude measure of resource riches) and found a significant association with conflict, although this has been challenged.21 They also found that greater male education to higher secondary level reduced the risk of war. They concluded that “greed” outperforms grievance in explaining conflict.

Failure of the social contract—Econometric studies show that the incidence of conflict is higher among countries with low per capita incomes, life expectancy, and economic growth.10,12,22 However, many statistical investigations of the association between vertical income distribution and conflict produce differing results.10,12,23 It has been suggested that funding programmes from the International Monetary Fund—usually associated with cuts in government services—cause conflicts, but neither statistical nor case study evidence supports this, perhaps because countries on the verge of conflict do not generally qualify for such programmes.12,24

Green war hypothesis—Here the evidence is contradictory. It seems that both environmental poverty and resource riches can be associated with conflict.13,16,25 Environmental stress tends to make people prone to violence as they seek alternatives to desperate situations (as in Rwanda), while resource riches give strong motivation to particular groups to gain control over such resources (as in Sierra Leone).

Although none of the four hypotheses solely explains all conflicts, they do identify factors likely to predispose groups to conflict. Clearly some explanations hold in some situations and not in others, but one factor that all studies have found to be important is a history of conflict. This is because the same structural factors that predisposed to war initially often continue, and because mobilising people by calling on group memories is more effective if there is a history of conflict.

Policies to reduce the likelihood of war

The research summarised above suggests some important policy conclusions for conflict-prone countries. One is that policies to tackle poverty and environmental degradation will reduce the likelihood of war, as well as being critical development objectives. Reducing large horizontal inequalities is essential to eliminate a major source of conflict. Policies that diminish private incentives to fight, especially once conflict is under way, are also needed. Above all, there is a need to secure inclusive government—from political, economic, and social perspectives—and a flourishing economy so that all major groups and most individuals gain from participation in the normal economy.

From a political perspective, inclusive government is not simply a matter of democracy; majority based democracy can lead to oppression of minorities. Conflict is greatest in semi-democracies or governments in transition and least among established democracies and authoritarian regimes.26 Democratic institutions must be inclusive at all levels—for example, voting systems should ensure that all major groups are represented in government. The recent constitution adopted for government in Northern Ireland and the proposals for Afghanistan and Burundi are examples of this.

Economic and social policies are needed to systematically reduce horizontal inequalities. Policies towards investment, employment, education, and other social services should aim at reducing imbalances and inequalities. Such policies need to be introduced cautiously since action to correct horizontal inequalities has occasionally provoked conflict by the group whose privileged position is being weakened, notably in Sri Lanka.

A major problem is that the government of a conflict-prone country may resist such action, since it may be the beneficiary of the imbalances. Outside agencies can point to the need to reduce horizontal inequalities, but ultimately such policies must depend on domestic actors.

In the short term, policies to change private incentives to fight include providing employment schemes and credit to young men. In the longer term, extending education and achieving inclusive development will enhance peacetime opportunities. Better control and legitimacy of international markets in drugs, timber, diamonds, etc, should reduce opportunities to profit from illegal trade during war.


Although this article has concentrated on the causes of conflict within countries, much of the analysis is relevant to the international situation. The sharp economic and social differences between Western societies and the Muslim world are a clear example of international horizontal inequalities. These, together with the widespread impoverishment in many Muslim countries, permit leaders such as Osama Bin Laden and Saddam Hussein to mobilise support only too effectively along religious lines.

Additional educational resources

  • Berdal M, Malone D. Greed and grievance: economic agendas in civil wars. Boulder CO: Lynne Rienner, 2000
  • Gurr TR. Minorities at risk: a global view of ethnopolitical conflicts. Washington DC: Institute of Peace Press, 1993
  • Horowitz D. Ethnic groups in conflict. Berkeley: University of California Press, 1985
  • Le Billon P, Macrae J, Leader N, East R. The political economy of war: what relief agencies need to know. London: Relief and Rehabilitation Network, 2000
  • Nafziger EW, Stewart F, Vayrynen R. War, hunger and displacement: the origin of humanitarian emergencies. Oxford: Oxford University Press, 2000
Examples of horizontal inequality


I thank the editor and two referees for their helpful comments.


Competing interests: None declared.


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5. Alexander J, McGregor J, Ranger T. Ethnicity and the politics of conflict: the case of Matabeleland. In: Nafziger EW, Stewart F, Vayrynen R, editors. War, hunger and displacement: the origin of humanitarian emergencies. Oxford: Oxford University Press; 2000. pp. 305–336.
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BMJ. 2002 February 9; 324(7333): 342–345.

Commentary: Conflict—from causes to prevention?

Douglas Holdstock, editor of Medicine, Conflict and Survival1-1001 and Antonio Jarquin, president1-1002

Modern war is not an expression of innate aggression but an economic and social construction.1-1 It is an attempt to settle, by violence, disputes over political power, territorial and ethnic issues, and societal stresses such as injustice and poverty. It is vital to address the roots of conflict. It is equally important to reduce the supply of arms, particularly to developing countries, as almost all of the approximately 30 currently active conflicts are in less developed countries,1-2 which, as Stewart notes, carry the main burden of deaths from war. According to the UN Development Programme, global military spending has fallen from a cold war peak of about $1 trillion (£709 million million) to around $750bn in 2000.

Treaties to regulate weapons (principally of mass destruction) do exist,1-3 but they need to be ratified by all UN members states, which should allow full scope for verification. It is regrettable that the United States is obstructing verification of the Biological Weapons Convention. Conflicts in developing countries are fought with conventional weapons, particularly small arms, which are recycled from one conflict to another and are light and simple to handle, even by children. The United Nations is attempting to curb the illicit trade in small arms, and a more radical treaty to limit arms transfers is being promoted by non-governmental organisations such as Oxfam. Destruction of arms should follow the end of conflict, and this could be facilitated by offering combatants retraining in exchange for arms.1-4

Stewart emphasises the importance of a history of conflict and comments that structural factors predisposing to war may persist. But many conflicts in developing countries—such as Afghanistan, Angola, and Nicaragua—began as cold war proxies. The European Union has made war between its members effectively unthinkable. Similar bodies, such as the Organisation for African Unity and others in Asia and Latin America, are developing and are likely to promote similar cohesion. Free dialogue between such groups at all levels is vital to reduce the very real risk of them becoming opposing “superstates” with an ethnic or religious basis.

To play its intended role—to “save succeeding generations from the scourge of war”—the United Nations must be reformed and strengthened. Member states must not undertake military action without UN authorisation; its role should not be confined to picking up the pieces after conflict.1-5 Eradication of war will not be easy but can be achieved piecemeal over time, and health workers have a key role.1-6 There is a medical model—the elimination of smallpox and soon of polio by surveillance, treatment, and preventive measures—for turning a vision into reality.


1-1. Groebel J, Hinde RA, editors. Aggression and war: their biological and social bases. Cambridge: Cambridge University Press; 1989.
1-2. Wallensteen P, Sollenberg M. Armed conflict, 1989-2000. J Peace Res. 2001;38:629–644.
1-3. Holdstock D. War: from humanitarian relief to prevention. In: McKee M, Garner P, Stott R, editors. International co-operation in health. Oxford: Oxford University Press; 2001. pp. 109–126.
1-4. Renner M. Small arms, big impact: the next challenge of disarmament. Washington DC: Worldwatch Institute; 1997.
1-5. Commission on Global Governance. Our global neighbourhood. Oxford: Oxford University Press; 1995.
1-6. MacQueen G, Santa-Barbara J. Peace building through health initiatives. BMJ. 2000;321:293–296. [PMC free article] [PubMed]

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