*! version 1.0 09mar2015

Title

syncmrates -- child mortality rates using synthetic cohort probabilities

Syntax

syncmrates
[varlist]

[weight]
[, options bootstrap_options

Main
t0(#) start of time interval in months

t1(#) end of time interval in months

testby(varname) test the difference in mortality rates between the two groups specified in varname

trend(#) calculates monthly series of mortality rates for # months before the survey

plot(string) plot monthly series of the mortality rate specified in string, where string can be nmr, pmr, imr, cmr, or u5mr

only iweights are allowed; see weight.

Description

syncmrates calculates the following mortality rates:

nmr neo-natal mortality rate

pmr post-neonatal mortality rate

imr infant mortality rate

cmr child mortality rate

u5mr under-5 mortality rate

syncmrates calculates mortality rates using the synthetic cohort probability method employed in Demographic and Health
Surveys(DHS) and described in Rutstein and Rojas(2003). This method is based on the full birth history survey approach, whereby women are
asked for the date of birht of each of their children, whether the child is still alive,
and if not the age at death.
By default mortality rates are calculated over the 5 years preceding the month interview.

Three variables must be included in varlist after issuing the syncmrates command in exactly the following order:
date of interview, date of birth, and age at death.
All three variables must be expressed in months and, following DHS convention,
date of of interview and date of birth must be expressed
in Century Months Codes (CMC). The CMC code takes the value of 1 in January 1900. When using non-DHS data, the date of interview,
and the date of birth have to be transformed using this code. For example, the CMC code for May 1968 is (1968-1900)*12+5.

syncmrates allows users to replicate exactly the mortality rates reported by DHS surveys. In addition:
1) it allows a flexible range for the time interval over which mortality rates are calculated.
While the default for the calculation of mortality rates is 5 years before the survey,
users can calculate mortality rates over 1 or 10 years before the survey or over any
other desired interval specified in the options t0(#) and t1(#);
2) it allows the calculation of mortality rates for geographic or socio-economic subgroups specified using if;
3) it calculates bootstrapped standard errors and 95% confidence intervals;
4) it calculates and tests the difference in mortality rates between two groups specified in testby(varname);
and 5) it builds monthly time series of monthly mortality rates and confidence intervals, it saves the series
in the current directory, and plots the mortality rate specified in plot(string) for exploratory data analysis

Options

Main

t0(#) set the start of the time interval in number of months before the survey,
the default is t0(61), corresponding to 5 years before the survey.

t1(#) set the end of the time interval in number of months before the survey,
the default is t1(1), corresponding to the first month before survey.

testby(varname) tests the difference in mortality rates between the two groups
specified in varname using boostrapped standard errors.

trend(#) produces monthly series of mortality rates and their confidence intervals
for the number of months before the survey specified in #. By default mortality rates are
calculated over a 5-year time interval before the survey but this interval can be changed
using the t0(#) and t1(#) options. The mortality rates for # monhts before the survey
are saved in the current directory in syncmrates.dta together with their 95% confidence intervals.

plot(string) can only be used with trend(#). It plots the monthly series of the mortality rate
specified in plot(string), where string can be either nmr, pmr, imr, cmr or u5mr.
The series are plotted for the number of months before the survey specified in trend(#).

Remarks

syncmrates calculates bootstrapped standard errors and confidence intervals for the mortality rates
and allows all stata bootstrap_options. The following options are of particular relevance in the
estimation of mortality rates:

reps(#): by default syncmrates uses 50 sample replications. The number can be increased in order
to obtain more accurate standard erros. The number can be reduced to speed computer calculations (down to a minimum of reps(2)) when
the user is interested in estimation of mortality rates but not in their confidence interval. In particular,
calculations employing the trend(#) option may require a long time using the default number of replications.

cluster(varname): by default, syncmrates calculates standard errors assuming the observations are independent.
More conservative standard errors can be obtained by assuming that observations are correlated within clusters and
independent across clusters. These standard errors are obtained using the option cluster(varname).

estat bootstrap: by default, syncmrates calculates normal-based confidence intervals that are symmetric around the mean
by 2 standard deviations. Non-symmetric percentile and bias-corrected confidence intervals can be obtained
by issuing the estat bootstrap command after syncmrates.

Examples

Mortality rates using DHS data

. syncmrates v008 b3 b7 [iw=v005]

Calculate more accurate and conservative standard errors

. syncmrates v008 b3 b7 [iw=v005], reps(1000) cluster(v021)

Mortality rates over 10 years before the survey

. syncmrates v008 b3 b7 [iw=v005], t0(121) t1(1)

Test difference in mortality rates between boys and girls

. syncmrates v008 b3 b7 [iw=v005], testby(b4)

Calculate trends over 10 years before the survey and plot trend of imr

. syncmrates v008 b3 b7 [iw=v005], trend(120) plot(imr)

References

Rutstein, S.0. and G.Rojas (2003). Guide to DHS Statistics,
Demographic and Healt Surveys, ORC Macro, Calvert, MD.

Author

Edoardo Masset

Institute of Development Studies

University of Sussex

Brighton, UK.

e.masset@ids.ac.uk