Transcript Time Location Sampling
Webinar Series on the Measurement of Child Protection
Overview of methods to collect data on children outside of family care Claudia Cappa Statistics and Monitoring Section, UNICEF, NY
Preliminary considerations
• Review conducted in the context of the US Government Evidence Summit on COFC • Definition of our target population • Identification/enumeration • Estimation of the population size • Additional information on living conditions etc
Differences in Vulnerabilities
Children in Institutions Armed Forces / Groups Child-headed Households Vulnerable Children Street Children Children in Detention Trafficked for Labor or Sexual Exploitation Separated or Unaccompanied due to conflict or natural disaster
Overall challenges
Methodological and practical
Isolated or hard to reach locations Live in conditions of illegality or secrecy Weakness of administrative data Stigma
Ethical
Consent Experience of trauma Follow-up Etc
Some specific challen ges
Street children
Main challenges: Lack of agreed operational definition and criteria for the identification of street children, intelligence gap and sampling issues
Children living in institutions
Main challenges: Many institutions are unregistered and many countries do not regularly collect/report data on children in institutional care
Methods Identified
• Time-Location Sampling • Neighborhood Method • Capture/Recapture • Respondent Driven Sampling • Household Surveys • Child Protection Information Management System • Child Labor Monitoring System • Establishment Surveys • Institution-Based Surveys • Administrative data on alternative care • Special Methods to Identify Children who Work
Criteria: reliability, validity and scope
• Reliability, i.e. extent to which the results of the methodology are consistent over time • Validity, i.e. extent to which the methodology actually achieves the intended purposes • Scope, i.e. extent to which the methodology can be used on a large scale and is generalizable to alternative settings
Time Location Sampling (TLS)
• • • • • • • • • • Time-Location Sampling Capture/Recapture Respondent Driven Sampling Neighborhood Method Child Protection Information Management System Child Labor Monitoring System Household Surveys Establishment Surveys Institution-Based Surveys and Databases Special Methods to Identify Children who Work • A probabilistic sampling strategy used to recruit members of a target population known to congregate at specific times in set venues • Step one: ethnographic mapping exercise of venues, days and times through key informants (law enforcement officials, NGOs, service provides, members of the target population) • Visit to the sites for verification and first enumeration • Selection of samples (two stage process) • Appropriate populations: Hard-to-reach, vulnerable, stigmatized, or hidden populations . May be useful with migrant or highly mobile populations.
Time Location Sampling (TLS)
• • • • • • • • • • Time-Location Sampling Capture/Recapture Respondent Driven Sampling Neighborhood Method Child Protection Information Management System Child Labor Monitoring System Household Surveys Establishment Surveys Institution-Based Surveys and Databases Special Methods to Identify Children who Work
Strengths
• Large and diverse sample • When appropriate weights are used = Representativeness (compared to simple convenience sample)
Limitations
• “Intelligence Gap”, i.e. difficulties in constructing a strong sampling frame • Possible bias • Access to venues • Proportion of missing • population
Capture/recapture sampling
• • • • • • • • • • Time-Location Sampling Capture/Recapture Respondent Driven Sampling Neighborhood Method Child Protection Information Management System Child Labor Monitoring System Household Surveys Establishment Surveys Institution-Based Surveys and Databases Special Methods to Identify Children who Work • • • Originally developed for animals Adapted to estimate size of human population groups that are mobile or have limited access to services for which no sampling frame is available Assumption: Group is closed (fixed size and composition) and the study area is complete Being capture does not change the likelihood of being captured in the future It is possible to identify individuals that have been captured previously Groups is homogenous and sources are independent All individuals have equal chances of appearing in each sample
Capture/recapture sampling
• • • • • • • • • • Time-Location Sampling Capture/Recapture Respondent Driven Sampling Neighborhood Method Child Protection Information Management System Child Labor Monitoring System Household Surveys Establishment Surveys Institution-Based Surveys and Databases Special Methods to Identify Children who Work
Strengths and limitations
• • • • • • Less vulnerable to external manipulation Weak evidence to show that the methodology generates the same results every time it is used Used for street children (Brazil) Rely on highly skilled interviewers Weather and mobility issues Risk of over-estimation (tendency to avoid re-capture)
Respondent driven sampling (RDS)
• • • • • • • • • • Time-Location Sampling Capture/Recapture Respondent Driven Sampling Neighborhood Method Child Protection Information Management System Child Labor Monitoring System Household Surveys Establishment Surveys Institution-Based Surveys and Databases Special Methods to Identify Children who Work • Type of snowball sampling that aims to overcome the potential bias associated with traditional snowball sampling methods • Used to recruit statistically representative samples of hard-to-reach groups by taking advantage of intragroup social connections to build a sample • Focus not on size but on representativeness
Respondent driven sampling (RDS)
• • • • • • • • • • Time-Location Sampling Capture/Recapture Respondent Driven Sampling Neighborhood Method Child Protection Information Management System Child Labor Monitoring System Household Surveys Establishment Surveys Institution-Based Surveys and Databases Special Methods to Identify Children who Work • Useful to quickly recruit large numbers of people from hidden population • Data collection can begin anywhere with a pool of eligible respondents (seeds and waves) • Double reward: being interviewed and recruiting others • Interviewers must ask the respondents to describe the relationship to the person who recruited him/her and how many people are known to be part of the population • Information used to make indirect estimates about the social network connecting the population and the proportion of the population in different groups • Good to capture children not in contact with services • Provide information on possible bias
Household Surveys
• • • • • • • • • • Time-Location Sampling Capture/Recapture Respondent Driven Sampling Neighborhood Method Child Protection Information Management System Child Labor Monitoring System Household Surveys Establishment Surveys Institution-Based Surveys and Databases Special Methods to Identify Children who Work • 400 clusters are selected with probability proportional to size, and about 20 households are selected and surveyed randomly from each cluster. • Appropriate populations: child-headed households & children unrelated to head of household
Strengths
• Global reach •Standardized methodology • Readily-accessible data
Limitations
•Weaknesses in its ability to identify unrelated children in a household
MICS Questionnaire for households
MICS4 Survey Design Workshop
MICS 2006
Children without parental care: the case of Burundi
Percentage of children aged 0-14 who are:
Database of institutions
• • • • • • • • • Time-Location Sampling Capture/Recapture Respondent Driven Sampling Neighborhood Method Child Protection Information Management System Child Labor Monitoring System Household Surveys Establishment/Hou sehold Surveys (Commercial Sexually Exploited Children) Databases of institutions Special Methods to Identify Children who Work
Acknowledgements: Tom Pullum, James Orlando, Meredith Dank, Susan Gunn, Maury Mendenhall and Kate Riordan