Titre alternatif

MAFE Senegal

Titre parallèle

Migrations entre l'Afrique et l'Europe - MAFE Sénégal (2008)

Pays

Nom	Abréviation
France	FR
Italy	IT
Senegal	SN
Spain	ES

Couverture géographique

• Six European countries and three African countries participated in the MAFE surveys. Data collection was carried out in both sending countries in Africa and destination countries in Europe, in order to constitute transnational samples. For MAFE Senegal, data was collected in Senegal (African part) and France, Italy and Spain (European part).

Univers

SENEGAL Household: Households selected randomly from the updated list of households in the selected primary sampling units. Two strata were distinguished: the households with migrants and those without migrants. Individual: People aged 25-75 at the time of the survey, born in Senegal and who have/had Senegalese citizenship. This lower age limit was set in order to obtain informative life histories. By not including respondents younger than 25, the resources were used more effectively. The place of birth criterion was used to exclude people who were born out of their country of origin in order to exclude second generation migrants in Europe and to increase the homogeneity of sample. Up to two return migrants and partners of migrants, and one randomly selected other eligible person. Return migrants were eligible if their first departure was above at 18 or over. EUROPE In all the European countries, the surveys were conducted among males and females who were aged 25 and over at the time of the surveys, and who were 18 or over when they had left Africa for the first time for at least one year. For MAFE Senegal, only migrants from Senegal were interviewed. This was a way to reinforce the homogeneity of the sample by excluding people of the 1.5 generation who are often "passive" migrants. In theory, surveyed individuals must be representative of the whole population with these characteristics in the departure region and in the destination countries. The sample is composed of males and females. In Europe, in spite of a gender demographic disequilibrium, the objective was to include 50% of males and 50% of females in order to allow gender analyses.

Type de données

survey data

Méthodologie

Dimension temporelle

Cross-section

Dates de collecte

Période	Libellé
2007-07 - 2007-08	Senegal pilot survey
2008-01 - 2008-06	Senegal (Dakar) survey
2008-03 - 2008-07	France survey
2008-03 - 2008-06	Italy survey
2008-05 - 2008-06	Spain survey

Fréquence de collecte

SENEGAL In Senegal, data collection activities started in November 2007 (selection of survey sites in Dakar and listing of households in the selected sites). They ended in September 2008 (data entry and data cleaning). Overall, 11 months were necessary to carry out all the activities related to data collection, and fieldwork lasted a little less than 6 months. Data collection was organized in two separate stages: the household survey was first conducted, and the biographic survey started after the household survey had been completed. The data collected in the household survey was used to prepare a sampling frame of individuals for the biographic survey; quick data entry of part of the questionnaires of the household survey was thus necessary before starting data collection for the biographic survey. Although this approach had advantages, it also lengthened the data collection process. This approach was not used for surveys in Ghana and DR Congo, where both surveys were conducted simultaneously. EUROPE In France, Italy and Spain the surveys were conducted in 2008, before the start of the EU funded project. Data collection activities lasted approximately 6 months. Note: A second round was carried in Spain in 2010. About 400 Senegalese migrants were interviewed using exactly the same questionnaire. The data will be released in the future. For more information, contact: pau.baizan@upf.edu

Procédure d'échantillonnage

• Probability: Stratified SENEGAL A three-stage stratified random sample was used. At the first stage, primary sampling units (census district) were selected randomly with varying probabilities. At the second stage, households were selected randomly in each of the selected primary sampling units (PSUs). At the third stage, individuals were selected within the households. a) Selection of primary sampling units (first stage) In the Senegal survey, the sample was designed to be probabilistic and representative of the Dakar region, and at the same time to maximize the chance of reaching households 'affected' by international migration (rare population). The sampling frame used to select the primary sampling units was the 2002 Population Census. The census districts (CD) -which are usually used as the primary sampling units in surveys in Senegal - have an average size of 100 households in urban areas. 60 primary sampling units were randomly selected at the first stage. This number of primary sampling units allows reaching a balance between a large dispersion of households (which decreases sampling errors) and a more concentrated sample (which reduces costs). The region of Dakar was divided into 10 strata of equal size, according to the % of migrant households within each of them (in average, 11.6% of the households were 'migrants'). 6 CD's per stratum were drawn, with a probability proportional to the number of households within each CD. In other words, census districts with a large number of migrants were more likely to be selected than those with low numbers of migrants. This approach increases the number of migrants interviewed in the individual survey, while still having a probabilistic sample representative of the target area. The listing of the households in the 60 selected primary sampling units was updated in order to select the sample of households. This stage was essential because a lot of changing occurred in some large neighbourhoods of Dakar since the previous census (2002), especially in suburban areas. This counting also allowed distinguishing between households with and without migrants. b) Selection of households (second stage) The following approach was used in MAFE-Senegal: - Households were selected randomly (using systematic random sampling) from the updated list of households in the selected PSUs. Two strata were distinguished: the households with migrants and those without migrants. A maximum of 50% of households with migrants were drawn in each district. Selected households that could not be reached (absence, refusals,…) were not replaced during the fieldwork. Replacement would distort the computation of sampling weights, and could also lead to bias the sample. To take account of refusals and absences of households, 22 households were selected to reach an effective sample size of 20 households per CD on average (a total of 1 200 households in Dakar region was to be reached). c) Selection of individuals (third stage) Next, individuals were selected within households for the life history survey. In each household, individuals were classified into 3 strata (which do not overlap): - Return migrants, who were aged 18 or over at their (first) departure (or whose age at departure is unknown) ; - Spouses/partners of migrants (if the spouse/partner is not a return migrant himself/herself) ; - Other people. Then, a simple random sample was done in each household to select: - Up to 2 return migrants (random selection if more than two in the households, all the return migrants were selected if not more than two in the household) - Up to 2 Spouses/partners of migrants (random selection if more than two in the household) - Another individual. In Senegal, an additional condition was that people had the Senegalese citizenship at birth. This condition was dropped in the Ghana and DR Congo surveys. Two types of questionnaires were used in the departure countries: the household questionnaire and the individual life history questionnaire. - The first questionnaire was used among a representative sample of households in the target region. - The second questionnaire was used among a sample of individuals in the selected households, targeting both return migrants and non-migrants. The household questionnaire was thus used as the sampling frame for the selection of individual respondents. EUROPE The objective of the survey was to obtain a sample 'as representative as possible' of the African populations (Congolese, Ghanaian, Senegalese) in the destination countries (150 individuals per origin and destination country). The way the sample was constituted may vary across countries, but some common principles were respected: - The composition of the sample should be as close as possible to the population of (Congolese, Ghanaian, Senegalese) migrants in the country in terms of gender, geographic distribution, age, socio-economic category or occupation. - One exception: the sample should be gender balanced. Males and females should be equally represented in order to allow gender analyses. - Samples in origin and destination may be linked, but migrants with weak or no relationships at origin should not be excluded from the sample. - Both documented and undocumented migrants should be represented in the sample. For MAFE Senegal, 200 Senegalese were to be sampled in each country (France, Spain and Italy). The quota method was preferred in France and Italy to collect information on Senegalese migrants. In Spain, a sample of Senegalese migrants was drawn in the Padron. This source appears as a unique sampling opportunity in Europe since it is annually updated and includes all migrants, even the undocumented ones. The Senegalese sample in Europe was made up from two types of samples: - a linked sample of respondents, whose contacts were obtained in Senegal through the household survey. The module D of the HH questionnaire was designed to help the collection of contacts. It had to be entered and transmitted securely to the destination countries before data collection started in Europe. The contacts validity was checked before the fieldwork began. For Senegalese in France, 156 contacts were collected but only 54% of them were actually usable (correct contacts but a large amount were not interviewed). In Italy, almost no contact could be used. The efficiency of this method varies a lot according to the context ; - an additional sample made up in each country to reach the expected sample size. The size of the additional sample is unknown until the contacts in the origin country have been obtained. The method of selection of this sample varied across countries (selection in a municipal register, through migrant associations, street recruitment, by snowballing methods…). Regions were selected to cover the largest possible population of Senegalese in the country. * France * - Target areas: 3 regions comprising 64% of Senegalese people in France (Ile de France, Rhône-Alpes and Provence-Alpes-Côte d'Azur) - Sample size: 201 - Quotas: By age, gender and socioeconomic status - Recruitment methods: Selection from contacts obtained in Senegal, public spaces, migrant associations, snowballing, interviewers' contacts * Italy * - Target areas: Lombardia, Emilia Romagna, Toscana, Campania - Sample size: 205 - Quotas: By age and gender - Recruitment methods: Selection from contacts obtained in Senegal, public spaces, migrant associations, snowballing, interviewers' contacts * Spain * - Target areas: 12 provinces: Almería (Andalucía), Alicante & Valencia (Comunidad Valenciana), Barcelona, Lérida, Tarragona & Gerona (Cataluña), Madrid (Comunidad de Madrid), Zaragoza (Aragón), Las Palmas (Islas Canarias), Murcia (Comunidad Autónoma de Murcia), Baleares (Islas Baleares) - Sample size: 200 (+ an additional sample of 400 people expected in 2010) - Quotas: Random sample from Padron - Recruitment methods: Population register (Padron), contacts obtained in Senegal, interviewers' contacts - Note: a quota was imposed and respected: the proportion of interviewed migrants living in areas with a large concentration of Senegalese residents had to be equivalent to the real proportion of Senegalese migrants living in those areas in the selected regions

Mode de collecte

Face-to-face interview: Paper-and-pencil (PAPI) The general strategy was the following one: 1. A household survey was conducted among a sample of households in the capital cities in Africa (household questionnaire in origin countries); 2. A life history survey among a sample of individual respondents was conducted in the departure countries (non migrants, return migrants and spouses of migrants). The individual respondents were selected from the households in the origin countries (individual questionnaire in origin countries); 3. A life history survey was carried out among migrants in destination countries (individual questionnaire in destination countries). All the surveys were done using paper questionnaires through face-to-face interviews. SENEGAL In Senegal, the survey was organized in two stages. The first stage consisted in collecting household data. At the end of that stage, selected data of the household questionnaire were entered in order to constitute the sampling frames for individual surveys in Africa and in Europe. The household survey thus precedes the collection of life histories both in Africa and Europe. NB: In Senegal, the interviewers who did the work in a household did also the work for the individuals of this precise household. It was a way to create a confidence relationship. The average duration of interviews for the household questionnaire was about 45 minutes-1 hour in Senegal. The average duration of the biographic questionnaire was also around 45 minutes, but it varied greatly depending on the age and migration status of the respondents. EUROPE In Europe, the moment for data collection depended on the selection method. In MAFE-Senegal, the fieldwork could start only after completion of the household survey. As a consequence, the fieldwork for the biographic questionnaires was done almost at the same time in all countries. The work of the interviewers included three stages: o The interviewers first had to set up an appointment with respondents by using the phone contacts or another source of recruitment (except in cases persons were directly available). Interviewers needed to confirm the appointment. The choice of the place and time of the interview were left to the respondents. o The interview was then done. The average duration of the interviews was approximately 1h45 in France. In most cases, interviews were carried out at the house of the respondents, but it also took places in various places (pubs, street, office…). The interviews were done during weekdays or week-ends, at various times. o Finally interviewers were asked to read quickly the completed questionnaire as soon as possible after the interview, in order to detect any missing parts or inconsistencies, and correct them on the spot. Approximately one additional hour was necessary for this. In all the countries, the respondents were offered a small gift at the end of the interview. In most countries, this was a calling card. The value of the gift varied between 5 € (Italy) and £15 (UK). In all the countries, the gift was very much appreciated. Although the gift was offered after the interview, some participants knew in advance they would receive it. Recruitment by snowballing also meant that respondents were sometimes aware they would receive a gift. Although this may have facilitated the recruitments of some persons, it may have affected negatively the composition of the sample.

Type d'instrument de collecte

Structured questionnaire The MAFE surveys rely on two different questionnaires: household and biographic. The questionnaires are almost entirely identical from one country to another. The few differences consist in: - Cultural variables (religion, ethnic groups, matrimonial status etc.) - New questions introduced on fostered children in the MAFE Congo and MAFE Ghana biographic questionnaires (Module on Children) - The order of the questions relating to migration in the household questionnaire (Module A) The Household Questionnaire: - Used only in African countries - Answered by a unique respondent who is usually the household head - Contains information on the members of the household (age, sex, education...) and also on people who live outside the household and who are related to it (head's children, partners living abroad, other relatives of the head or his/her spouse who live abroad and with whom the household has been in touch within the last 12 months). The questionnaire includes a specific module aimed at obtaining contact information for each of the declared migrants. In addition, it contains specific modules on short migration histories, on relationships between each migrant and the household, and on housing conditions and owned assets. - Topics: socio-demographic variables of each individual, short migration histories, remittances, household assets, housing history - Available in French (MAFE-Senegal, MAFE-Congo) and English (MAFE-Ghana) The Biographic Questionnaire: - Used in all African and European countries - Answered by the migrant him/herself - Contains life histories of all the surveyed individuals, whatever their migratory status at the time of the survey (non-migrant, return migrant, current migrant). The questionnaire contains retrospective information on the following topics: dwelling, family, work, international migration of the interviewee (including attempts to migrate, return trips to Senegal, transit migration and legal status in foreign countries), migration history of the migrant's relatives (list of their stays abroad, including dates and country names), goods and assets, and remittances and contributions to associations in the country of origin. - A grid was used, jointly to the questionnaire, to help the interviewee to recall important dates of his/her history - Topics: family formation, education and employment, housing, migration, investments (housing, business, community amenities or infrastructure)... - Available in French (MAFE-Senegal, MAFE-Congo), English (MAFE-Ghana), Italian and Spanish (MAFE-Senegal)

Caractéristiques de la collecte

The MAFE surveys collect information on potentially vulnerable populations (undocumented migrants) and on sensitive subjects (remittances, legal status…). In order to facilitate the fieldwork and increase the quality of the data, it was important to carefully inform the people who were to be interviewed. The legal pre-requisites changed according to the country. In France (only), a legal authorization had to be obtained before starting the fieldwork. The CNIL (Commission nationale informatique et libertés) was concerned by the way the contacts were going to be obtained in Senegal and, most of all, by the sensitivity of certain variables contained in the questionnaires (ethnic group, religion). We obtained the authorization to ask these questions, but in order to keep them in our files, we had to ask to the interviewees to sign a written informed consent. According to legal prescriptions, in all European countries, a letter was designed to explain their rights to the interviewees. In Senegal, no specific document was designed. In most countries, a leaflet was designed and used to sensitize respondents and authorities about the MAFE project. In advance of the survey, several communication actions have been undertaken: - In Africa, inform neighbourhood heads / municipalities of survey by an official letter or by a visit - Use local radio / migrants radio and chat show to present the survey - Inform an organisation of migrants who can support the survey - Visit the key places of the community (churches…) Because of the complexity of the questionnaires, only interviewers with a good experience in complex surveys were recruited. In African countries, it was highly recommended to hire the same interviewers to conduct both household surveys and individual surveys. This approach proved to be very efficient in all the surveys. In Europe, interviewers had to be able both to recruit the migrants and to fill correctly the questionnaire. As a general rule, it was preferable to have a relatively small number of well-trained interviewers than a large number of interviewers. Overall, around 20 to 25 interviewers and supervisors were involved in data collection in each country. The number of the interviewers per survey varied between 8 (survey among Ghanaians in the UK) and 17 (Netherlands). In all the countries, both male and females interviewers were hired; most of them had higher education and some experience with data collection. In some countries (e.g. France), some of them were professional interviewers. The selected interviewers were not necessarily from the same country as the respondents, but most of them also had foreign origins. For instance, 7 of the 12 interviewers in Belgium were of foreign origin, 5 of them from DR Congo. In the Netherlands, most interviewers were from Ghanaian origin. The fact that many of the interviewers were themselves of foreign origin seemed to have positively influenced the willingness of interviewees to participate in the survey. Directly after being filled, questionnaires were checked by the interviewers and supervisors. They were then sent to a small team of editors for an in-depth reading. The editors consisted of 9 people in Senegal, 6 in Ghana and 5 in DR Congo. The team had followed the same training as the interviewers, and also received a specific training for editing the questionnaires. Data entry was performed using MS Access programs prepared by Ined.

Traitements

Taux de réponse

SENEGAL In the MAFE Senegal survey, the quantitative objectives were not completely fulfilled: - The selected number of households was 1320 in Senegal, but only 1141 were successfully interviewed, including: - Non-migrant household : 458 - Household with at least 1 returnee: 205 - Household with at least 1 current migrant: 617 - Household with returnee(s) and current migrant(s): 139 This represents a response rate of 86.4% (90% was expected). For the biographic questionnaire, 1 387 individuals were selected, only 1 062 were interviewed, including: - Returnees: 193 - Partners left behind: 101 - Other non-migrants: 768 At the end, the drop was of 23.6%, while a drop of 10% was expected. The overall response rate in Senegal is 66.1%. EUROPE 600 Senegalese migrants were successfully interviewed: 200 in France, 198 in Spain, and 202 in Italy.

Autres formes d'évaluation des données

A methodological note entitled "Sampling international migrants with origin-based snowballing method: New evidence on biases and limitations", written by Cris Beauchemin and Amparo González-Ferrer, can be found in the study's related materials, as well as another methodological note in french "Biais de non-réponse dans l'enquête Migrations entre l'Afrique et l'Europe (MAFE-Sénégal)" written by Nicolas Razafindratsima, Stéphane Legleye and Cris Beauchemin.

Pondération

SENEGAL The computation of sampling weights relies on computing sampling probabilities at each stage. The product of sampling probabilities at each stage gives the overall sampling probability. Taking the inverse of the sampling probability gives the inflation factor. These factors are adjusted (taking into account non-response and by trimming the weights). They are then normalized, so that the sum of weights is equal to the sample size. The initial "household weighting" takes into account the sampling probability of the DR and then the households. It was corrected by the non-response by multiplying it by the opposite of the rate of answer, estimated by strata of the DR and strata of the household (only available variables for the answering and non-answering households). The initial "individual weighting" is equal to the product of the rectified household weight and of the opposite of the sampling probability in the household. It also has corrected by the non-response by multiplying it by the opposite of the rates of answer of the individuals, calculated by homogeneous groups obtained by logistic regression. The explanatory variables kept for this regression were the strata of the individual, sex, age, the size of the household, and the rank of contact. EUROPE In the European countries, similar sample sizes were selected for males and females, resulting in an overrepresentation or underrepresentation in the MAFE samples. Similarly, older people were usually oversampled. For these reasons, post-stratification weights are computed to give each observation its proper weight and to match the samples as closely as possible to selected population characteristics. Senegalese migrants in France and Italy were selected using quota sampling with quotas set by age groups and sex, while the sample in Spain was a probabilistic sample from the population register, augmented by Senegalese respondents identified through contacts in the household survey in Senegal. Given this mix, weights for Spain were also computed by poststratification and not by computing sampling probabilities. The procedure for constructing post-stratification weights in the case of MAFE-Senegal consisted of the following steps: - Computation of target population estimates - Computation of initial inflation weights - Computation of poststratification weight In the MAFE data, all survey weights have been rescaled (normalized) so that the sum of weights corresponds to the sample sizes of households and individuals respectively while the mean of the weight variables equals one. For further details about weights, please read the MAFE methodological note 6 entitled "Sampling and Computation Weights in the MAFE Surveys" (see related materials).

---