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Explore Brass' Growth-Balance & Hill's Generalized Growth-Balance methods for assessing completeness of death reporting in demographic analysis. Identify coverage measure & correction factors using related spreadsheets.
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Workshop on Demographic Analysis and Evaluation
Adjustment of Mortality • In this part of the workshop we will cover indirect techniques for assessing the completeness of death reporting using: • The Brass’ Growth Balance Method • Hill’s Method
Brass' Growth-Balance Method This technique estimates the completeness of reporting of deaths over age 5 in relation to information on population. It compares the distribution of deaths in relation to the distribution of population, both by age. Spreadsheet: GRBAL.xls
Brass' Growth-Balance Method • Data required: • Deaths by age, preferably in 5-year age groups. • Population with the same age and sex breakdown as deaths. • If possible, the time reference for the population should be midyear of the year to which the deaths pertain.
Brass' Growth-Balance Method • Assumptions: • The population is stable. • Degree of completeness of deaths reporting is uniform above age 5 or 10 years. • No age misreporting of the population or of deaths.
Brass' Growth-Balance Method • Procedure: • Calculate cumulated population for ages x and over by cumulated population reported in each age group 5+, 10+ … • Calculate cumulated deaths for the same ages • Calculate partial death rates: ratios of cumulated deaths to cumulated population • Calculate partial birth rates: ratios of population age x to population ages x+ • Plot the partial birth and death rates and fit a line to the plotted points
Brass' Growth-Balance Method • Procedure: • The slope of a fitted line represents completeness of coverage of deaths reporting • Deaths may then be adjusted using the completeness of coverage adjustment factor
Brass' Growth-Balance Method Method implemented in PAS spreadsheet: Spreadsheet: GRBAL.xls
Brass' Growth-Balance Method After required data are entered into the spreadsheet by the analyst, the spreadsheet will automatically apply the calculations described above, to fit lines to observed points… Spreadsheet: GRBAL.xls
Brass' Growth-Balance Method Spreadsheet: GRBAL.xls
Brass' Growth-Balance Method The analyst then has the following tasks: 1. Review observed points on graph. 2. Review lines fitted to observe points, as generated with the default age group settings of the PAS spreadsheet; and change the defaults as needed to improve fit of lines. (You will have two lines to work with.) 3. Identify the line with best fit. 4. Take note of the completeness measure and correction factor associated with line containing the best fit. Program: GRBAL.xls
Brass' Growth-Balance Method Correction factors Completeness measures Spreadsheet: GRBAL.xls
Brass' Growth-Balance Method • Advantage: • The technique provides an estimate of the coverage of deaths, and that estimate is remarkably robust to violation of the assumptions of the method.
Brass' Growth-Balance Method • Limitations: • Rapid changes in mortality or fertility will affect the results of the method. • Migration will also have an effect on the results if the age structure of the migrants differs from that of the population. • Age misreporting and differential completeness of reporting of population by age affect the estimated adjustment factor. • Estimation of completeness of deaths reporting refers only to ages 5+.
Hill's Generalized Growth-Balance Method Brass’ growth-balance method (Brass 1975, United Nations 1983) estimates completeness of deaths reporting beyond childhood under strong assumptions about the demographic stability of a population.
Hill's Generalized Growth-Balance Method Hill’s generalization builds on the earlier work by Brass (Brass 1975, 1979; United Nations 1983), and the work by Martin (1980), and Preston and Hill (1980) but (1) allows for evaluation of either deaths or bracketing censuses, and (2) allows for an intercensal interval other than 5 years. Hill’s method estimates relative completeness of two census enumerations and of intercensal registered deaths.
Hill's Generalized Growth-Balance Method Data required: • two censuses by age and sex • deaths by age and sex during the intercensal period (or an estimate of deaths for this period)
Hill's Generalized Growth-Balance Method Assumptions: • Population is closed to migration. • Population is demographically stable. • Completeness of death recording is constant at all ages above some childhood age “a.” • Completeness of census coverage is constant across ages.
Hill's Generalized Growth-Balance Method • Procedure: • The general equation (Hill 1987, p.9) • The growth rate
Person-years lived Entries to the population Intercensal deaths Hill's Generalized Growth-Balance Method
Hill's Generalized Growth-Balance Method • Final estimation equation
Hill's Generalized Growth-Balance Method • Final estimation equation Spreadsheet: HillGGB.xls