Sources of Vital statistics Data analysis and Report

Sources of Vital statistics Data analysis and Report writing workshop

What are vital statistics?

Population and institution based sources Population-based data sources are those that are representative of the whole population surveys, censuses civil registration. Institution-based data sources are those collected routinely from administrative and operational activities, Health Information Systems (HIS) hospital discharge data, police records for attended deaths, social security records. health facility surveys, where data are collected in an institution.

Routine vs period collections Routinely collected administrative CRVS HIS/ Hospital information Health facility data Periodic collection Censuses Surveys data

Census collections Primary source of mortality data in PICTs A population census is a compulsory, universal and simultaneous enumeration of the national population, conducted on a periodic basis. Provide population denominator data AND mortality data Information on births and deaths may be derived directly indirectly from changes in population (by age and sex) based on survival and migration reliant on accurate migration data

Census. . . a compulsory, universal and simultaneous enumeration of the national population, conducted on a periodic basis Censuses provide denominators (population) for computing fertility and mortality indicators Can also provide numerators (births and deaths), and data for indirect estimation of mortality through a question on retrospective events

Calculating mortality from a census Direct measures ask about births and deaths in the household over a nominated reference period – usually within the last 12 months. Take a complete birth history (not usually used in the census) Indirect measures collect some information on births and deaths then approximate when these events would have occurred. Children ever born –children surviving Orphanhood Widowhood These measures can then be used as inputs for model life tables that generate estimates of age-specific measures of mortality and LE. Models that use a single input parameter based on childhood mortality have been shown to have a tendency to under-estimate mortality in PICTs

Periodic Surveys i. e. Demographic and Health Surveys (DHS) and the UNICEF Multi. Indicator Cluster surveys (MICS). not ongoing data collections, but are collected in a specific period of time. collect data for a proportion of the population considered to be representative of the broader population of interest. may collect data to undertake direct estimation of mortality from reported deaths, or indirect estimation based on the age distribution methods described previously. The reliability of estimates from survey data is driven by how well the sample selection reflects the broader population of interest Surveys are also subject to recall bias, and response bias

Birth history questionnaire

Problems with using birth histories Recall Reference period Inaccurate reporting from respondents Sample size in low mortality countries Cultural appropriateness Length of the questionnaire

Routine vital registration collections Civil registration provides a legal basis for the recording of vital events such as live births & deaths In most developed countries, it is a legal requirement that: a medical practitioner completes a death certificate whenever anybody dies vital events, such as births and deaths, are registered An efficient routine CRVS system, with medical certification of Co. D, provides ongoing and relatively low cost data collection and therefore timely mortality data for decision making upheld as the “gold standard” for birth and death data

medical certificate considered the reference standard for Co. D information, in the absence of an autopsy, as a qualified practitioner is required to assess the case and make an informed decision concerning the sequence of events that led to the death

Civil Registration Dual function – establish civil status, collect data for planning Citizen’s / government responsibility Passive system, as opposed to special registration activities Multiple government agencies responsible Data transmission losses, need for inter-sectoral collaboration Difficulties in cause attribution in some situations Data may not be timely without strong incentives to report As the legal record, civil registration of vital events is frequently legislated as the official source for mortality data despite not always being the most reliable data source in country.

Core functional areas for CRVS and underlying support needs • For good evidence for policy and planning – all of the components must be functioning well • Strong CRVS systems are multi-sectoral

Figure 5. 1: Diagram of the reporting and registration processes for deaths Family Local Government Office (Island Council etc) Civil Registrars Office (Ministry of Justice) National Statistics Office National Planning Office / Process Ministry of Health

Example Routine Death Reporting System Health System Doctor* Nurse# Family Notice of Death Town Officer Monthly report District Officer Quarterly report Prime Ministers’ Office Civil Registrars Office (Ministry of Justice) Death Certificate Medical Certificate of Death Health Information System Monthly report Public Health Nursing National Statistics Office National Planning Office / Process

Health registration of vital events Vital events such as births and deaths are also often recorded through routine data collections within the health system. health data collections are primarily to inform operational decisions, and Co. D is central to this purpose. may include medical certificates community nursing reports, facility based data Must consider if this is population based data or facility based data

Proportion of estimated deaths reported by Island group Tonga 2005 -2009: Reconciled data – unadjusted

Proportion of estimated deaths reported by gender, source and period, Tonga 2001 -2009: Two-source analysis

Demographic surveillance sites A demographic surveillance system captures all vital events in a specified area. Often combined with disease detection (sentinel surveillance) used in PNG unlikely to be a suitable solution in other PICTs with small populations

Summary of Population based Data Collection Approaches for Mortality Data Source Census Survey Periodicity Data collection (mortality level data) Direct - (deaths in the household) Indirect – partial birth history (CEB/CS) & orphanhood data Direct – complete birth history Co. D Data Collected? No Retrospective Indirect - partial birth history (CEB/CS) No Retrospective Varies Possible using verbal autopsy Whole population (depending Current on coverage) Hospital cases only Current Direct reporting of event Yes Continuous Varies – usually targets sub. Current population of specific interest. Direct reporting of event Usually limited Continuous Selected areas – usually not representative of whole population over time. Direct reporting of event Yes Periodic – 5 -10 years DHS MICS Other household based surveys Routine vital Civil registration Registration Health vital registration Hospital discharge records Other Various routine databases Demographic surveillance Sites Sample frame Whole Population Periodic – ~ 5 years Selected sample – representative of whole population Periodic – 2 stage clustered sample – ~ 5 -10 years representative of whole population Usually once- Varies off Continuous Period of interest Retrospective Current No (source: Carter, 2013)

Institution-based data sources in the health sector primarily include those based at hospitals and health centres In the hospital setting, unit record data on deaths and Co. D may be collected through hospital separation data (hospital records that indicate whether the patient was discharged home from hospital, transferred to another facility or died). Co. D is based on the principal diagnosis at the time of death Countries may also collect data on deaths through primary or community health care nursing programs, deaths recorded on a separate form to be sent to the local area nursing manager and/or recorded on monthly reports.

Registries source of outcome data i. e. – cancer registries, pregnancy registers May be population or institution based Population registries much more common where there is national testing facilities tend to be more useful for measures of morbidity rather than mortality (as they are generally a secondary data source in this case). For deaths: registries record anyone who dies WITH the disease rather than FROM the disease (as the designated underlying cause) therefore the data is not directly comparable to that obtained from vital registration. Pregnancy registers often maintained at health facility level, but rarely electronic and generally not centrally collated.

Data sources to ascertain causes of death pathological autopsy report (gold standard) physician certification at time of death physician certification in absentia, using medical records lay assignment of cause verbal autopsy – interview with relatives of deceased to identify symptoms leading to death

Where does your data come from? Think about the data you brought to the course and where it comes from… Why was it collected? How was it collected and by whom? What are the strengths and weaknesses of that data collection? What impact is that likely to have on your data?