@article{Tjaden2021,
  author    = {Tjaden, Jasper},
  title     = {Measuring migration 2.0},
  series = {Comparative migration studies : CMS},
  volume    = {9},
  journal   = {Comparative migration studies : CMS},
  number    = {1},
  publisher = {Springer},
  address   = {London},
  issn      = {2214-594X},
  doi       = {10.1186/s40878-021-00273-x},
  pages     = {20},
  year      = {2021},
  abstract  = {The interest in human migration is at its all-time high, yet data to measure migration is notoriously limited. "Big data" or "digital trace data" have emerged as new sources of migration measurement complementing 'traditional' census, administrative and survey data. This paper reviews the strengths and weaknesses of eight novel, digital data sources along five domains: reliability, validity, scope, access and ethics. The review highlights the opportunities for migration scholars but also stresses the ethical and empirical challenges. This review intends to be of service to researchers and policy analysts alike and help them navigate this new and increasingly complex field.},
  language  = {en}
}
@article{TjadenHaarmannSavaskan2022,
  author    = {Tjaden, Jasper and Haarmann, Esther and Savaskan, Nicolai},
  title     = {Experimental evidence on improving COVID-19 vaccine outreach among migrant communities on social media},
  series = {Scientific reports},
  volume    = {12},
  journal   = {Scientific reports},
  publisher = {Springer Nature},
  address   = {London},
  issn      = {2045-2322},
  doi       = {10.1038/s41598-022-20340-2},
  pages     = {10},
  year      = {2022},
  abstract  = {Studies from several countries suggest that COVID-19 vaccination rates are lower among migrants compared to the general population. Urgent calls have been made to improve vaccine outreach to migrants, however, there is limited evidence on effective approaches, especially using social media. We assessed a targeted, low-cost, Facebook campaign disseminating COVID-19 vaccine information among Arabic, Turkish and Russian speakers in Germany (N = 888,994). As part of the campaign, we conducted two randomized, online experiments to assess the impact of the advertisement (1) language and (2) depicted messenger (government authority, religious leader, doctor or family). Key outcomes included reach, click-through rates, conversion rates and cost-effectiveness. Within 29 days, the campaign reached 890 thousand Facebook users. On average, 2.3 individuals accessed the advertised COVID-19 vaccination appointment tool for every euro spent on the campaign. Migrants were 2.4 (Arabic), 1.8 (Russian) and 1.2 (Turkish) times more likely to click on advertisements translated to their native language compared to German-language advertisements. Furthermore, findings showed that government representatives can be more successful in engaging migrants online compared to other messengers, despite common claims of lower trust in government institutions among migrants. This study highlights the potential of tailored, and translated, vaccination campaigns on social media for reaching migrants who may be left out by traditional media campaigns.},
  language  = {en}
}
@misc{TjadenHaarmannSavaskan2022,
  author    = {Tjaden, Jasper and Haarmann, Esther and Savaskan, Nicolai},
  title     = {Experimental evidence on improving COVID-19 vaccine outreach among migrant communities on social media},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Wirtschafts- und Sozialwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Wirtschafts- und Sozialwissenschaftliche Reihe},
  number    = {156},
  issn      = {1867-5808},
  doi       = {10.25932/publishup-58740},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-587409},
  pages     = {10},
  year      = {2022},
  abstract  = {Studies from several countries suggest that COVID-19 vaccination rates are lower among migrants compared to the general population. Urgent calls have been made to improve vaccine outreach to migrants, however, there is limited evidence on effective approaches, especially using social media. We assessed a targeted, low-cost, Facebook campaign disseminating COVID-19 vaccine information among Arabic, Turkish and Russian speakers in Germany (N = 888,994). As part of the campaign, we conducted two randomized, online experiments to assess the impact of the advertisement (1) language and (2) depicted messenger (government authority, religious leader, doctor or family). Key outcomes included reach, click-through rates, conversion rates and cost-effectiveness. Within 29 days, the campaign reached 890 thousand Facebook users. On average, 2.3 individuals accessed the advertised COVID-19 vaccination appointment tool for every euro spent on the campaign. Migrants were 2.4 (Arabic), 1.8 (Russian) and 1.2 (Turkish) times more likely to click on advertisements translated to their native language compared to German-language advertisements. Furthermore, findings showed that government representatives can be more successful in engaging migrants online compared to other messengers, despite common claims of lower trust in government institutions among migrants. This study highlights the potential of tailored, and translated, vaccination campaigns on social media for reaching migrants who may be left out by traditional media campaigns.},
  language  = {en}
}
@misc{Tjaden2021,
  author    = {Tjaden, Jasper},
  title     = {Measuring migration 2.0},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Wirtschafts- und Sozialwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Wirtschafts- und Sozialwissenschaftliche Reihe},
  number    = {149},
  issn      = {1867-5808},
  doi       = {10.25932/publishup-55387},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-553873},
  pages     = {20},
  year      = {2021},
  abstract  = {The interest in human migration is at its all-time high, yet data to measure migration is notoriously limited. "Big data" or "digital trace data" have emerged as new sources of migration measurement complementing 'traditional' census, administrative and survey data. This paper reviews the strengths and weaknesses of eight novel, digital data sources along five domains: reliability, validity, scope, access and ethics. The review highlights the opportunities for migration scholars but also stresses the ethical and empirical challenges. This review intends to be of service to researchers and policy analysts alike and help them navigate this new and increasingly complex field.},
  language  = {en}
}
@article{Tjaden2023,
  author    = {Tjaden, Jasper},
  title     = {Web scraping for migration, mobility, and migrant integration studies},
  series = {International migration review},
  journal   = {International migration review},
  publisher = {Sage Publications},
  address   = {Thousand Oaks},
  issn      = {0197-9183},
  doi       = {10.1177/01979183231208428},
  year      = {2023},
  abstract  = {Web scraping, a technique for extracting data from web pages, has been in use for decades, yet its utilization in the field of migration, mobility, and migrant integration studies has been limited. The field faces notorious limitations regarding data access and availability, particularly in low-income settings. Web scraping has the potential to provide new datasets for further qualitative and quantitative analysis. Web scraping requires no financial resources, is agnostic to epistemic divides in the field, reduces researcher bias, and increases transparency and replicability of data collection. As large providers of digital data such as Facebook or Twitter increasingly restrict access to their data for researchers, web scraping will become more important in the future and deserves its place in the toolbox of migration and mobility scholars. This short and nontechnical methods note introduces the fundamental concepts of web scraping, provides guidance on how to learn the technique, showcases practical applications of web scraping in the study of migrant populations, and discusses potential future use cases.},
  language  = {en}
}
@article{TjadenGninafon2022,
  author    = {Tjaden, Jasper and Gninafon, Horace},
  title     = {Raising awareness about the risk of irregular migration},
  series = {Population and development review},
  volume    = {48},
  journal   = {Population and development review},
  number    = {3},
  publisher = {Population Council},
  address   = {New York},
  issn      = {0098-7921},
  doi       = {10.1111/padr.12468},
  pages     = {745 -- 766},
  year      = {2022},
  abstract  = {In response to mounting evidence of harm inflicted on irregular migrants along their journeys from West Africa to Europe, international organizations, civil society organizations, and governments have scaled up campaigns as a tool for raising awareness about the risks of irregular migration. Campaigns aim to counter misinformation by smugglers and facilitate safe migration decisions. Despite the growing number of interventions, there is limited empirical evidence on the impact and effectiveness of such campaigns. Based on a difference-in-difference design, this study investigates the effect of a mobile cinema and community discussion intervention on the perceptions, knowledge, and intentions of potential irregular migrants in Northern Guinea in 2019. The results show that potential migrants who participated in events were significantly more likely to show awareness gains and less likely to report high intentions to migrate irregularly. While the relative importance of risk perceptions and their impact on migration flows remain unclear, the findings provide evidence supporting the assumption that risk awareness can be a relevant factor in the decision-making process of potential irregular migrants. While campaigns may be an effective tool in certain contexts, effect sizes highlight the need for policymakers to keep realistic expectations.},
  language  = {en}
}
@article{Tjaden2022,
  author    = {Tjaden, Jasper},
  title     = {Risky journeys},
  series = {International migration},
  volume    = {61},
  journal   = {International migration},
  number    = {2},
  publisher = {Wiley-Blackwell},
  address   = {Oxford},
  issn      = {0020-7985},
  doi       = {10.1111/imig.13003},
  pages     = {212 -- 225},
  year      = {2022},
  abstract  = {In response to well-documented harms inflicted on irregular migrants attempting to travel from West Africa to Europe, various actors have scaled up information interventions to counter misinformation by smuggling networks and facilitate safe migration decisions. Many interventions include information on the potential dangers involved in migration. However, there is a striking lack of empirical evidence assessing a key assumption of campaign effectiveness, that is the relationship between risk perceptions and the decision to migrate irregularly. This study contributes an empirical account based on two independently collected surveys in Senegal and Guinea. Consistent with rational choice theories on migration decisions under uncertainty, the results suggest that higher risk perceptions are consistently and strongly associated with reduced intentions to migrate irregularly. Yet, the explanatory power of risk perceptions depends on context and is generally less important than structural and socio-economic factors.},
  language  = {en}
}
@article{TjadenSpoerlein2023,
  author    = {Tjaden, Jasper and Sp{\"o}rlein, Christoph},
  title     = {How much do "local policies" matter for refugee integration?},
  series = {International migration review},
  journal   = {International migration review},
  publisher = {Sage Publications},
  address   = {Thousand Oaks},
  issn      = {0197-9183},
  doi       = {10.1177/01979183231205561},
  year      = {2023},
  abstract  = {A growing number of studies have recently postulated a so-called local turn in the study of immigrant and refugee integration policy. A fundamental, yet untested, assumption of this body of research is that local (sub-national) policies and administrations shape how migrants and refugees integrate into society. We develop and apply an analytical model using multilevel modeling techniques based on large-N, longitudinal survey data (N > 9000) with refugees (2012-2018) in a highly decentralized country (Germany) to estimate the scope for local policy effects net of individual-level and state- and district-level characteristics. We show that region and district-level variation in integration outcomes across multiple dimensions (employment, education, language, housing, social) is limited (∼5\%) within 4-8 years after immigration. We find modest variation in policy indicators (∼10\%), which do not appear to directly translate into outcomes. We discuss implications for the study of local policies and the potential for greater convergence between administrative and political science, interested in governance structures and policy variation, and sociology and economics, interested primarily in integration outcomes.},
  language  = {en}
}
@article{NdashimyeHebieTjaden2022,
  author    = {Ndashimye, Felix and Hebie, Oumarou and Tjaden, Jasper},
  title     = {Effectiveness of WhatsApp for measuring migration in follow-up phone surveys},
  series = {Social science computer review},
  journal   = {Social science computer review},
  publisher = {Sage},
  address   = {Thousand Oaks},
  issn      = {0894-4393},
  doi       = {10.1177/08944393221111340},
  pages     = {20},
  year      = {2022},
  abstract  = {Phone surveys have increasingly become important data collection tools in developing countries, particularly in the context of sudden contact restrictions due to the COVID-19 pandemic. So far, there is limited evidence regarding the potential of the messenger service WhatsApp for remote data collection despite its large global coverage and expanding membership. WhatsApp may offer advantages in terms of reducing panel attrition and cutting survey costs. WhatsApp may offer additional benefits to migration scholars interested in cross-border migration behavior which is notoriously difficult to measure using conventional face-to-face surveys. In this field experiment, we compared the response rates between WhatsApp and interactive voice response (IVR) modes using a sample of 8446 contacts in Senegal and Guinea. At 12\%, WhatsApp survey response rates were nearly eight percentage points lower than IVR survey response rates. However, WhatsApp offers higher survey completion rates, substantially lower costs and does not introduce more sample selection bias compared to IVR. We discuss the potential of WhatsApp surveys in low-income contexts and provide practical recommendations for field implementation.},
  language  = {en}
}