their step-by-step journey through Libya.

There are differences between the migration journey through Libya along the Western and the Eastern routes. Migration through the Western route almost always takes place in stages (Wittenberg, 2017). Migrants use smugglers to avoid the large number of checkpoints that have to be crossed, though there are few reports of detention and deportation along the routes heading north. Anecdotal evidence indicates that migrants from West African countries often stop in a locality until they save enough money (often by being employed informally) to be able to continue their journey (UNHCR, 2017b). The journey through the Eastern route is instead non-stop, characterized by strict cooperation between smugglers and human traffickers, and often involves cases of violence. In recent years, this journey has become very short, between ten days and three weeks (Micallef, 2017).

# **4 Data**

## **4.1 Migration data**

Data on migrants and their movements are retrieved from the IOM’s Libya Displacement Tracking Matrix (DTM). The IOM-DTM is the only source providing reliable data on migration flows in Libya. The DTM tracks the movements of migrants in Libya using the data collected at the IOM Flow Monitoring Points (FMPs) in the Libyan territory.<sup>13</sup> FMPs are located at important points of transit and permanence of migrants such as border crossings, bus stations, harbors, markets, public squares, areas where migrants look for work, etc. (IOM, 2016).

Migrants included in the DTM dataset live close by a FMP and are able to move across the country. These migrants are not victims of human trafficking or imprisoned in detention centers.<sup>14</sup> Most of them often remain for long periods in a given location, live in rented houses, and have a job (often informal) (IOM, 2018b, 2019).

In our empirical analysis, we use DTM data for the period June 2017 to February 2020.<sup>15</sup> The DTM collects information on migrants located in, arriving to, and departing from the area around each FMP. For each FMP, it reports the three most common countries of origin, the three most common countries of destination, and the share of migrants by length-of-stay category (i.e., less than 2 weeks, less than 3 months, between 3 and 6 months, more than 6 months). Data are collected daily and reported weekly. In our analysis, we aggregate them at the monthly level.

The primary method of data collection at the Flow Monitoring Point (FMP) is through Key

> 13The IOM definition of migrant does not distinguish between legal and illegal migration. Yet, as discussed in Di Maio et al. (2023), migration flows recorded by the DTM are likely to be mostly made of irregular migrants.

> 14According to the Libyan immigration law, individuals entering the country without a permit are at risk of detention at any time. The Directorate to Combat Illegal Migration (DCIM) (established in 2012 to tackle irregular migration flows into the country) is in charge of arresting and organizing the deportations of irregular migrants, and managing the detention centers. While immigration law is rarely enforced, migrants arrested and detained often face severe abuses by security forces and militias, including torture, rape, extortion, forced labor, and extra-judicial execution (Mixed Migration Centre, 2019). The living conditions in the detention centers remain an issue of grave concern with serious humanitarian consequences for the migrants detained (UNSMIL, 2018). In 2019, 4,700 migrants (around 1% of the total migrant population) were in detention centers.

> 15The period of analysis begins with the first wave of the DTM data for Libya (2017) and ends with the beginning of the COVID-19 pandemic (March 2020).

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