"Grievance" stands for the argument that people rebel over issues of identity, e.g. ethnicity, religion, social class, etc., rather than over economics.
These motivations are manifested in multiple ways, including economic gain through control of goods and resources or by increased power within a given state.
The strong case for the "greed" argument was made by Paul Collier and Anke Hoeffler in a study they performed for the World Bank in 2000.
This is because natural resources may lower the startup cost of war, and provide rebels with an easy way of financing prolonged conflicts.
[2] Therefore, Collier and Hoeffler conclude that on their own, most variables that seek to explain civil war onset through measurements of grievance alone prove insufficient.
Further, they find that ethnicity, religion or any cultural or demography characteristic do not seems to have a positive relationship with civil war onset.
As rebel organizations need to be fairly large to have a significant impact and incite a civil war, the looting of primary commodity resources is the best way for them to maintain financial viability.
[4] Examples of this include diamonds in Sierra Leone and Angola, timber in Cambodia, coca in Colombia, and poppy in Afghanistan.
The higher a state's dependence on primary commodities, the greater the risk of conflict; this is due to the resources being a main financial component of rebel groups and a weak governmental structure.
[8] Elite groups within weak states attempt to harness economic agendas and resources within a given civil society and are motivated to create private profit by mobilizing violent means.
When state control breaks down, trade that was previously prohibited is more easily facilitated and has the potential to generate substantial amounts of profit for those involved.
Extracting benefits from aid that is sent to a conflict area is also beneficial for rebel groups as there are often possibilities to raid resources sent from abroad.
The small group of elites surrounding Milosevic perpetuated conditions that warranted international sanctions in order to better control trade and loot resources.
In south central Asia, along the lawless Afghani-Pakistani border a group called the Taliban have been engaging in what could best be described as a greed based insurgency since 2001.
The Taliban's insurgency is in opposition to the NATO and United States supported Afghan transitional government of Hamid Karzai.
One of the primary characteristics of a Greed-based conflict as listed above is the ability to derive income or revenue from natural resource predation.
In these ways the Taliban are able to fund their insurgency and begin to fall under the characterization of a group of actors in pursuit of greed based conflict.
Pakistan's role encompasses a number of characteristics important to the greed model; ethnic homogeneity, a supply of unskilled labor, and lawless borderlands.
Collier and Hoeffler discuss the idea that diversity makes conflict more difficult as it is harder to mobilize a heterogeneous ethnic base into rebellion.
The insecurity and lack of formal state governance over the Afghan south-east and the Pakistani west also makes a significant contribution to the robustness of a greed based argument here.
[17] Therefore, the Inter-Service Intelligence Agency (ISI) of Pakistan has been known to directly support the Taliban with funding, tip offs, and the corruption of government officials.
They became involved in opium trade, were provided with weapons, and began to construct the organizational aptitude that allows for their continued success today.
The war that took place in Sri Lanka was due to the perceived grievances that the Tamil population experienced during Sinhalese rule.
It was grievances such as a perceived disadvantage over education possibilities, work opportunities, language use and economic prospects that increased the ethnic tensions between the two groups and drove the Tamil Tigers to start a war.
As seen with Sri Lanka, these factors are more likely to drive conflict since they also provide a specific environment where charismatic leaders can pick on the grievances and create a sense of group membership that facilitates the outbreak of war.
His ideas look into the specifics of complex emergencies, which is a term officially defined by the InterAgency Standing Committee (IASC) as:"A multifaceted humanitarian crisis in a country, region or society where there is a total or considerable breakdown of authority resulting from internal or external conflict and which requires a multi-sectoral, international response that goes beyond the mandate or capacity of any single agency and/or the ongoing UN country program.
He spoke of Collier's work and said, "This is where econometrics tips over into arrogance and starts closing down the possibility of a genuine understanding of conflicts or, by extension, of a political settlement that addresses underlying grievances".
He disagrees with the quantitative research methods of Collier and believes a stronger emphasis should be put on personal data and human perspective of the people in conflict.
This isn't necessarily a complete dismissal of the greed vs. grievance theory, but rather a critique on its polarity and methods of data collection.
Beyond Keen, several other authors have introduced works that either disprove greed vs. grievance theory with empirical data, or dismiss its ultimate conclusion.