responding to frustrations and challenges. However, the war also resulted in women becoming economically active, which in this case decreased IPV, as the pressure on men to provide for their families reduced. Also, economic independence and interventions provided women with the option of leaving a violent relationship. Thus, IPV risk is linked to both formal and informal social structures that create gender inequality, including financial dependence on men, traditional gender norms surrounding masculinity as well as the broader changes in social norms and behaviors related to interpersonal violence that occur during conflict.

# 4. Data and model specification

# 4.1 Data and sample construction

Data are drawn from the 2008 and 2013 Nigerian Demographic and Health Survey (NDHS), which include Domestic Violence (DV) modules that sample 23,752 and 27,634 women respectively.<sup>16</sup> The NDHS includes information on the location of the interview and its GPS coordinates. Observations from the 2008 NDHS provide data for the period before the BH insurgency while observations from the 2013 NDHS provide data for the period during the BH insurgency. Exposure to BH conflict is measured using the Armed Conflict Location and Event Database (ACLED), which records events whether they generate fatalities or not. The data on events are reported by date, location, agent and type.

Our sample is made up of data drawn from 664 Local Government Areas (LGAs) across all 36 states, including the Federal Capital Territory (FCT). Observations from the 2008 and 2013 NDHS are linked to the BH events recorded in ACLED using the GPS coordinates <mark>provided in both data sets. To match the timing of the NDHS surveys, we use geocoded BH events that occurred between 2009 and 2013.</mark><sup>17</sup> During this period, 799 BH events in Nigeria were recorded in ACLED. Because of the intensity of the BH insurgency, interviewers during the field work of the 2013 NDHS could not reach some conflict-affected areas (NPC 2014). As we exploit variations in the timing and location of BH events, observations from the 2008 NDHS from LGAs not surveyed in the 2013 NDHS - Maidugiri in Borno State and Damaturu and Nangere in Yobe State - are excluded from our analysis.

# 4.2 Outcome variables

Both the 2008 and 2013 NDHS DV modules follow international global standards for the measurement of intimate partner violence. Ever partnered women were asked questions about experiences of violence using a modified version of the Conflict Tactics Scale (Straus 1990), a commonly used instrument in both the DHS and stand-alone violence against women and girls surveys.<sup>18</sup> To measure experience of physical or sexual IPV, women are asked if they ever

> 16 The NDHS is a nationally representative cross-sectional household survey that provides data on population, health, and nutrition for women <mark>aged 15-49.</mark>

> 17Because the ACLED often reviews specific periods of conflict to ensure accuracy, there may be changes to the data in selected countries or targeted conflicts throughout the year. The ACLED data used for the analysis in this study were downloaded from www.acleddata.com on August 30, 2018.

> 18 Sociologist Straus (1990) developed the original Conflict Tactics Scale (CTS), which consists of a series of individual acts of physical and sexual violence (Straus, 1979, 1990). The modified list used by the NDHS includes only fewer acts of physical and sexual violence (see appendix section A2). If a woman confirms that any one of the

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