Despite global commitments to reduce violence and associated deaths by 2030, the world has seen a significant increase in deadly violence. This increase may be due to factors such as violent extremism, the adaptability of criminal networks and gangs, political instability and the emergence of fragile states.1 2 Violence has grown to be a significant public health issue as victims, including children, women and men, may experience long-term effects like addiction, physical and mental health problems and disabilities. Violence entails the use or the threatened use of harmful force by an offender or perpetrator on a victim. Oftentimes, murder, assaults, rape, assassinations and other violent acts have violence as the aim, whereas terrorism, extortion, robbery and other crimes use violence as a means. Broadly speaking, violence can be lethal or non-lethal, with non-lethal violence resulting in non-fatal physical, sexual or psychological abuse, which can contribute to morbidity over a person’s life course, particularly for women and children.3 Coping skills developed in response to non-lethal violence can also lead to life-threatening conditions, including HIV/AIDS, heart disease, stroke and cancer.3 4

Lethal violence, on the other hand, results in the death of oneself or others and can be classified differently, depending on the approach. Homicide, suicide, domestic violence, interpersonal violence, gang violence, mass shootings, terrorism, war and conflict are all examples of lethal violence. Homicide can be intentional or unintentional, and it involves unlawfully killing someone, usually with violence.4 Suicide is classified as lethal violence because it results in the intentional death of oneself. It is the fourth leading cause of death among 15–29 year-olds worldwide.5 Domestic violence is common in intimate relationships, including those between married, cohabiting and dating partners, as well as those between other family members.6 7 Although it does not always result in death, it is increasingly carrying some elements of lethality, including intimate partner homicide. Gang violence kills and is perpetrated by organised groups, usually as a result of territorial disputes, drug trafficking and retaliation, accounting for 19% of all global homicides in 2017.4 Terrorism aims to instil fear and exert control over people by using violence or the threat of violence, which results in fatalities and injuries.

Lethal violence is complex and results from a variety of factors such as socioeconomic contexts, norms and individual motivations, among others. Being young, male and from a low socioeconomic background increases one’s chances of becoming a victim or perpetrator of lethal violence.8 In Nigeria, lethal violence results from a variety of factors, including the country’s history of colonialism, poverty and inequality, political instability, ethnoreligious conflicts, gang violence, domestic violence and state failure, which has resulted in several ungoverned spaces. Nigeria’s history is littered with lethal violence, beginning with interethnic clashes spawned by colonialism and leading to the Nigeria-Biafra civil war (1967–1970). Specifically, ethnic, religious and politically motivated violent crises over time, as well as the terrorist insurgency since 2009, have all contributed significantly to Nigeria’s lethal violence burden. Since 2006, Nigeria, for example, has recorded over 143 000 violent deaths from more than 30 000 fatal incidents.9 These fatalities are headlined by violent clashes over control of oil resources in Nigeria’s South-South, farmer–herder conflicts in the North-Central, terror activities in the North-East, armed banditry by criminal gangs in the North-West, separatist agitations in the South-East and general criminality in the South-West. As a result, lethal violence is prevalent throughout Nigerian society, leaving a high toll of fatalities in its wake.

Adult mortality rates, especially in developing countries, are a critical public health indicator usually used to measure socioeconomic development.10 Adult mortality rates describe the probability of people aged 15 dying before their 60th birthday when the age-specific death rates apply to the years between those ages.11 Although there has been a decrease in adult mortality worldwide, this reduction is more significant in developed countries compared with developing countries like Nigeria.12 Several factors including HIV/AIDS, high blood pressure, pregnancy and childbirth complications, non-communicable diseases, poverty, terrorism and injuries contribute to high adult mortality in developing countries.10 13–15 Lethal violence is one of the leading causes of mortality among adult populations aged 15–44 years worldwide, accounting for an estimated 10% of all years lived with disabilities.8 16–18

Nonetheless, most developing countries, including Nigeria, pay insufficient attention to violence-related mortality when compared with maternal and child mortality, which is prioritised by the global community. As a result, most mortality studies ignore lethal violence as a factor in Nigeria’s mortality experience.9 19 There is no evidence of studies that examined violence-related fatalities in Nigeria over a multiyear period. As a result, a closer examination of lethal violence as a mortality risk factor is required for a better understanding of Nigeria’s overall mortality experience over time. Consequently, we focused on the overall trends and patterns of violence-related mortality in Nigeria between 2006 and 2021 in this study. We specifically examined: the trends of deadly violence across Nigeria as a whole to demonstrate its dynamics over time, and violence-related mortalities by state to highlight the geography of violent deaths across Nigeria. We also looked at the relative number of violent deaths per 100 000 people in Nigerian states to better understand violent deaths concerning population size and violence-related fatalities by cause, with the goal of investigating the various types of violence that contribute to Nigeria’s mortality rate.

The study’s emerging findings may have local and international implications by emphasising the role of lethal violence in the mortality trajectory. As a result, targeted preventive measures aimed at reducing lethal violence in Nigeria and elsewhere may emerge. Furthermore, the number of years covered in this study will provide a broader horizon for a comprehensive understanding of the nature and dynamics of violence-related deaths, as well as for programmes and policies aimed at mitigating them. As a result, it could pave the way for an epidemiological approach to studying lethal violence in Nigeria and other countries where it is prevalent. In general, by providing data on the types of violence, their causes and victim characteristics, this study could help measure the global march towards achieving the Sustainable Development Goals (SDG) of reducing violence by 2030.

Nigeria has 36 states, 1 Federal Capital Territory (FCT) and 774 local government areas (LGAs), including six in the FCT. This study included these 36 states as well as the FCT. Nigeria Watch (NW) provided secondary data for this study. NW, which was founded in 2006, is a database and ongoing research project that monitors lethal violence, conflicts and human security, and archives fatality reports since 1 June 2006, to address the scarcity of data on victims of violence.9 The Institut Français de Recherche en Afrique hosts it at the University of Ibadan in Nigeria. The NW is a member of the Casualty Recorders Network, an organisation that promotes standards and international humanitarian and human rights law. The Japanese International Cooperation Agency and the Managing Conflict in Northeast Nigeria are currently funding the NW Project. The Institut de Recherche pour le Développement, Paris, and Britain’s Department for International Development (DFID) (until 2017) support NW.

The NW database remains Nigeria’s most comprehensive database on lethal violence and human security because it archives all sources of information as scanned PDF documents, allowing users to easily track previous records for reference. The database’s statistics are reliable because it is consistent and has used the same approach since 2006. NW records lethal violence by date and location (state, LGA, town, village or ‘offshore zone’). The police, the judiciary, hospitals and human rights organisations (primarily Human Rights Watch and Amnesty International) provide information to the NW database. Other sources include private security firms, companies, embassies and Nigeria’s major national dailies. Although the database is far from complete, it reflects a bias in Nigeria’s press, such as under-reporting, over-reporting and differences in reported figures. To address this issue, the NW team uploads as many reported figures as possible from as many sources as possible to the database, which generates an average number of deaths for each violent incident.

The variables involved in this study are lethal violence and mortality. NW defines a violent event as any act that leads to a fatality in one or several contiguous LGAs and terminates when there are no deaths recorded. Included in this definition are state-sanctioned acts such as the execution of convicted criminals and fatalities resulting from operations by government security forces. Lethal violence as applied in this study is subdivided into two: intentional (homicide, cultism, etc) and unintentional (road traffic crashes, etc). Mortality as applied in this study entails the loss of life of a person irrespective of age and gender resulting from any violent act.

The causes of violent deaths vary and, in this study, include acts such as land issues (incidents related to land disputes but exclusive of fatal cattle grazing disputes), political issues (incidents related to political events; eg, elections, or the control of political power in general), religious issues (incidents justified on religious grounds) and market issues (incidents related to economic competition and control of market areas, including bus stations but exclusive of all issues). Others are cattle grazing (incidents that oppose cattle breeders between themselves or against farmers), crime (all other fatal criminal incidents including robbery, banditry, rape, domestic violence, etc, but excluding political, religious, market, land, cattle and sorcery issues), convicts execution (death penalty executed by government officials, excluding extrajudicial killing, lynching and jungle justice), sorcery (incidents related to occult societies, human sacrifices, witchcraft) and other incidents (undefined incidents that lead to death). Also, included in the causes of violent deaths are unintentional acts such as road traffic crashes. Road traffic crashes are considered unintended violence by NW because they often involve the use of vehicles as a weapon and result in serious injuries or death. This is especially important as they are usually the result of reckless or negligent behaviours, in which a driver overspeeds, drives under the influence of drugs or alcohol and puts the life of road users at risk of serious injury or death, even when not intended.

The data set used in this study covers 36 states and the FCT from January 2006 to December 2021. The data cover fatalities resulting directly from intentional or unintentional violence such as banditry, cultism, insurgency, road crashes and cattle grazing. NW does not record suicides except for two cases: suicide attacks perpetrated by terror insurgents and the murders of security operatives running amok before killing themselves.

The data for this study were exported into an Excel spreadsheet and subjected to descriptive statistical analysis at the univariate level. To explore the trends of lethal violence in the country, the absolute number of deaths was calculated per year (2006–2021). Subsequently, the result was presented in a chart illustrating its dynamics over time. To explore the geographical patterns of violence-induced mortalities, the absolute number of deaths resulting from violence recorded across the 36 states and the FCT was mapped and illustrated by states. To calculate the relative number of deaths due to lethal violence, the total number of violent deaths per state was divided by the total population of each state and multiplied by 100 000. Lethal incidents across the 36 states in Nigeria and the FCT are also recorded by adapted and updated population figures per LGA based on the 1991 and 2006 censuses and the annual growth rate as calculated per state. Such makes it easier to calculate the relative number of deaths per 100 000 inhabitants. To understand the various causes of violence-related mortalities, available data were disaggregated into cattle grazing, convicts execution, crime, land issues, market issues, natural disasters, oil distribution, oil production, other incidents, political issues, insurgency, road crashes and sorcery. This represents the total number of violent deaths by cause. For further nuanced insights into the cause of violent deaths, the three major causes of violent deaths (crime, insurgency and road crashes) were further interrogated to illustrate their patterns and dynamics. The absolute number of deaths resulting from each of the causes of violent deaths was calculated in absolute terms and presented in charts.

This study is one of the few studies to chart a trend analysis of violent deaths across Nigeria from 2006 to 2021 in light of Nigeria’s mortality experience. We used secondary data from the NW database. Following the analysis of the data, trends and patterns in violent deaths, the geography of deadly violence, the relative number of violent deaths per 100 000 populations and the cause of violent deaths emerged, revealing the prevalence of deadly violence throughout the country over time. Hence, it indicates that deadly violence remains a significant contributor to Nigeria’s mortality trajectory, even though this is often not at the front burner in mortality studies in Nigeria.

The study revealed widespread deadly violence across the 16 years we investigated. The years 2013–2015 were particularly brutal, with violent deaths rising from 2013 to a peak in 2014, a pre-election year, with a lot of violence either before or after. This finding is consistent with previous findings.20 During this period, terror groups, Boko Haram and ISWAP were quite active, causing havoc in the North-East and in the North-West and North-Central states. However, the absolute number of violent deaths declined sharply in 2016 and 2017, only to rise again steadily from 2018 to 2021, mainly due to bandit activities in the North-West and North-Central regions. The pervasive violence across Nigeria can be attributed to the presence of ungoverned spaces, allowing violent and criminal elements to operate freely. The findings are consistent with previous studies and reports.19 21–26

Furthermore, every state had a fair share of violent deaths throughout Nigeria, with only Ekiti State recording less than a thousand violent deaths. Regardless of the variations of deadly violence across the country, it was more prevalent and intense in northern Nigeria than in the southern region. Our findings suggest regional variations and are consistent with other studies elsewhere.27–31 For instance, of the nine states with the highest record of deadly violence, six are in northern Nigeria, with Borno having the highest number of violent deaths and Jigawa the lowest. Fatalities in Borno State were attributed to Boko Haram and ISWAP insurgent activities and military interventions since 2009. In Lagos State, cult groups were the main cause of deadly violence. In Kaduna and Zamfara States, bandits were responsible for the majority of fatalities. Plateau, Benue and Delta States also had high numbers of violent deaths, mainly due to land issues involving Fulani herders and indigenous farmers and sectarian violence between indigenous Christians and Muslim settlers. Ekiti, Ebonyi and Enugu recorded the lowest number of deaths from deadly violence in the southern region. The disparity in the number of violent deaths among states within the same zone highlights the complexity of lethal violence. Other organisations that track violent conflicts and fatalities32–34 also reported findings that were consistent with these findings, naming Zamfara, Kaduna, Borno, Benue and Niger as the most violent states in 2021.

Further findings revealed the Nigerian states with the highest relative number of violent deaths per 100 000 populations. Findings identified Borno, Plateau, Zamfara, Nasarawa, FCT, Yobe and Adamawa as states with the highest relative number of violent deaths per 100 000 populations, and by extension the most dangerous states in Nigeria within the years under review. These states have a history of sectarian crises, and frequent clashes between ethnic nationalities, and some are the epicentres of the Boko Haram/ISWAP insurgency. For instance, Borno State had the highest relative number of deaths per 100 000 populations. Previous studies have reported a similar number of violent deaths from terror activities in northern Nigeria.4 35 Sheats et al reported that suicide accounted for 16.8 while homicide accounted for 5.7 violent deaths per 100 000 populations in 39 states and the District of Columbia in the US states.31

Lagos and Ogun States recorded the highest relative number of deaths per 100 000 populations and consequently the most dangerous states in the South-West. Both states continuously record numerous lethal road crashes, especially along the Lagos-Ibadan, Lagos-Abeokuta and Lagos-Badagry highways. Petrol tanker crashes are common along major transport corridors. In the South-South, Delta and Bayelsa States were the most dangerous with relative deaths per 100 000 people. Road traffic crashes, communal clashes, militancy and pipeline vandalism headline fatalities in both states. Anambra and Ebonyi States in the South-East had the highest relative number of deaths per 100 000 populations. Intercommunity clashes and general criminality are common in both states, as are pro-Biafra separatist agitations. On the other hand, Jigawa, Ekiti, Kano, Akwa Ibom, Kebbi and Sokoto recorded the lowest relative number of deaths per 100 000 populations across the country and by extension the least dangerous states to live in. However, these findings contrast with a report36 which identified Bauchi, Nasarawa, Adamawa and Yobe as the safest states in the first quarter of 2022. The contrast in findings may be due to the period under review, with the study covering 16 years and the Cable report only covering the first quarter of 2022 and not controlling for population strength.

Causes of lethal violence in Nigeria varied by contexts ranging from crime, natural disaster, oil distribution, other incidences (all causes that were not predefined causes of lethal violence), political issues, road crashes, cattle grazing, convicts execution, market issues, land conflicts, insurgency and sorcery. While crime affected all 36 states and the FCT, the same could not be said about cattle grazing. For instance, cattle grazing was reported across 35 states and the FCT except Lagos State. It was not that there were no conflicts between herders and farmers but such incidents did not culminate in deaths. Only five states, Edo, Enugu, Rivers, Lagos and Plateau, recorded cases of convicts execution while land conflict resulted in deaths in 34 states and the FCT except Sokoto and Yobe States. There were no deaths from market issues in Bauchi, Borno, Jigawa, Kebbi, Niger, Osun, Sokoto, Taraba, Yobe and Zamfara States while Kebbi State failed to record a fatality from oil distribution. Oil production led to fatalities in 10 states: Abia, Akwa Ibom, Anambra, Bayelsa, Cross River, Delta, Edo, Imo, Kogi and Rivers, while insurgency was reported in 18 states across Nigeria.

Between 2006 and 2021, many communities across the 36 states and the FCT were faced with different forms of violent crimes. General criminal activities mostly caused violent deaths across Nigeria. Rural banditry and cultism were the major cause of crime-related mortalities. In the North-West region alone, banditry was responsible for a significant number of violent deaths between 2006 and 2021. Rural banditry and counteroperations by government forces claimed about 17 646 lives. Armed bandits continue to cause unrest across different states in Nigeria, especially in the North-West where raids on rural communities, kidnapping for money and rustling cattle have become prevalent with loss of life in its wake. Victims of bandit attacks cut across civilians, government forces and bandits themselves, many of whom were killed by government troops on special counteroperations. For instance, Operation Forest Sanity, Operation Thunder Strike, Operation Whirl Punch and Operation Hadarin Daji were all special counteroperations to dislodge the bandits. This finding is consistent with previous findings about the prevalence of armed banditry in Nigeria.37 38 Reports have also linked dispersed Boko Haram and ISWAP fighters to the increasing banditry and violent deaths in northern Nigeria.39 40

Cult-gang violence is also a significant source of violent deaths across the country and elsewhere.28 Cult violence is most prevalent in southern Nigeria, with Rivers, Lagos, Edo, Delta and Nasarawa being the states with the highest number of cult-related deaths. The high crime rate and the metropolitan nature, which made Rivers and Lagos States centres for socioeconomic and political activities, contributed to the high number of cult-related fatalities in both states. The quest for territorial control mostly characterises cult clashes in the most affected states.27 41 Clashes regularly involve rival cult groups. For instance, in Lagos State, the Aiye and Eiye confraternities have been the dominant groups and have, over the years, clashed over supremacy. Unlike in Nigeria’s south, cultism is not prevalent in the north. The five states with the least number of cult-related deaths are from the region. One previous study recorded similar findings on the prevalence of cult-gang activities in southern Nigeria.42 For instance, more than 100 cult groups in Rivers State alone are causing incalculable human and economic losses. According to a 2020 report by SB Morgan on violence in Rivers State, more than 100 cult groups are fuelling violence in Rivers State and have caused incalculable human and economic loss.43 In Lagos State, cultism has infiltrated traders and road transport unions, with factional clashes common among the two dominant cult groups, Aiye and Eiye.44

Insurgency represented another major source of deadly violence in Nigeria. Although military establishments and civilians were the main targets of insurgent attacks, intergroup supremacy clashes between Boko Haram and ISWAP, the search for new territories and the competition for resources contributed to the escalation of violence and the increase in casualties.45 The group rivalry worsened following Abubakar Shekau’s death, the leader of the Boko Haram terror group, in May 2021, and the attempts by ISWAP to absorb his Boko Haram commanders and foot soldiers. The incessant intergroup clashes, coupled with intensified raids on Boko Haram/ISWAP enclaves in the Sambisa Forest and the constant surrender of its fighters to government troops, forced many insurgents to seek new territories in the North-West and North-Central, particularly Niger and Kaduna States, leaving a high toll in loss of life in their trail.46 47

Despite the Nigerian Federal Road Safety Corps’ best attempts to reduce road traffic crashes, the alarming number of fatalities from road traffic crashes in this study is concerning. It confirms that road traffic crashes are a major public health issue in the country, resulting in a large number of deaths, disabilities and injuries.48 49 This finding is consistent with the worldwide recognition that road traffic crashes are a global epidemic and the leading cause of injury-related deaths.50 The fact that road traffic crashes are Nigeria’s third leading cause of overall deaths, the leading cause of trauma-related deaths and the most common cause of disability emphasises the problem.50 The high death toll resulting from road crashes is not only due to bad roads. They are also the result of negligent and careless behaviours on the part of drivers and a combination of other factors, leading to preventable loss of life.51 52 WHO reported a significant increase in road traffic injuries and deaths since 2000, with about a 50% increase in healthy life years lost.8 Previous studies in Nigeria have documented high mortality from road traffic injuries. A study found mortality from road traffic injuries to be 1.6 per 1000 people.53 Another study reported that an overall 8516 deaths resulted from road crashes across Nigeria between 2006 and 2015.19

Furthermore, a high proportion of violent deaths resulted from deadly violence especially in the North-Central due to farmers and herders’ conflict. The discovery of cattle grazing as a cause of deadly violence in Nigeria reveals serious issues concerning land conflicts and their impact on both farmers and Fulani communities in Nigeria’s North-Central region. The conflicts are primarily focused on open-grazing massacres and lethal attacks on farming communities. The data in figure 10 depict the changing trends in fatalities over time. The discovery implies that the conflicts are not cyclical and can occur at any time of year, confirming the notion that they have no seasonal pattern.54 Factors such as climate change, drought, urbanisation and the resulting scarcity of land for farming and grazing all contribute to the escalation of violence.55–58 Climate change has reduced available land for farming and grazing, increasing competition between farmers and herders.58

At this point, there is a need to note that there are potential limitations to the NW database. Therefore, caution should be observed while generalising the findings in this paper. The database is far from exhaustive as some incidents could be unreported while others are sometimes under-reported or over-reported by some news media. Therefore, fatality figures for the same incident could differ from one news media to another due to dysfunctions in journalistic practices. However, to fix such a challenge, the NW Project team uploads as many figures as reported and allows the database to generate an average number of deaths for such violent incidents. Regardless of these potential limitations, the database aids chart a trend in lethal violence and better understanding its contributions to Nigeria’s mortality experience.