CMGPDLN Methodological Lecture Day 2 Strengths and Weaknesses

CMGPD-LN Methodological Lecture Day 2 Strengths and Weaknesses of the CMGPD-LN

Historical population databases • • Parish registers Genealogies Censuses Household registers

Table A. 1. Comparison of features of sources for historical demography Parish registers Longitudinal X Individuallevel X Vital statistics Censuses X X Detail on households Genealogies Household registers X X X Geographic specificity X X Complete community X X X Population at risk Timing of vital events X X X

CMGPD-LN Relative Strengths • Household and village of residence – Not available in genealogies, parish registers • Longitudinal – Not available in censuses • Complete recording of the at-risk population – Not available in parish registers • Time-depth/Multigenerational – Not available in most household registers • Kinship – Genealogies typically only record a single descent group • Prospective – Genealogies are retrospective

CMGPD-LN Limitations • Omission of boys who died in infancy and early childhood – Can’t really do infant or early child mortality – Underestimate fertility • Omission of daughters • No non-state occupations, or landholding – Landholding will be able in Shuangcheng (CMGPDSC)

Average numbers of boys and girls born in next 3 years to married men aged 15 -50

CMGPD-LN Limitations • Missing registers – Event-history analysis limited to registers for which immediately following register is also available • Unrecorded deaths – A small % of individuals who were probably dead, were carried on alive from register to register as if they were alive – Creates problems at advanced (80+) ages

Using the Data RECORD_NUMBER • RECORD_NUMBER identifies the same observation across the different datasets • Use as the basis for one-to-one merge local cmgpd_ln_location ". . CMGPD-LN from ICPSRICPSR_27063“ use "`cmgpd_ln_location'DS 000127063 -0001 -Data“ merge 1: 1 RECORD_NUMBER using "`cmgpd_ln_location'DS 000327063 -0003 -Data"

Using the Data RECORD_NUMBER • If the merged datasets won’t fit into memory, make use of options on use and merge to load specific variables use RECORD_ID YEAR SEX using "`cmgpd_ln_location'DS 000127063 -0001 -Data“ merge 1: 1 RECORD_NUMBER using "`cmgpd_ln_location'DS 000327063 -0003 -Data“, keepusing(NON_HAN_NAME) tab YEAR if SEX == 2, sum(NON_HAN_NAME)

Using the Data Missing Values • Following standard practice, missing values are coded as -98 or -99 – -98 is structural missing – -99 is missing • These are not the same as STATA missing, so observations will not be excluded automatically • Especially in regressions, computations of means, etc. , either manually exclude these, or recode to force exclusion – recode ZHI_SHI_REN -99 -98=. or – summ ZHI_SHI_REN if ZHI_SHI_REN != -98 & ZHI_SHI_REN != -99