In
demographic data the most important and common error is committed in recording
of ages. Ages are recorded in whole numbers in completed years. Extract date of
birth are seldom asked, even if exact date of birth are known, the date is
tabulated with a reference to date in incomplete year which creates biased over
above ages are misstated due to conscious acts and same times unconsciously
wrong ages are recorded. Studies of various ages data revealed that following
type of misstatement of ages are usually recorded.

An over statement of ages before adult hood and under statement
afterward. An over statement of ages of person just below 65 years an over
statement of ages toward extreme of life. A heaping of ages at 21 years for
male and 18 years for female. Heaping of ages of ending digits which are
multiple of 5 that are 0 and 5 there after even digits or odd digits ages not
studies not recorded not stated or unknown.

Various method of studying and measuring error in ages reporting have
been develop some of them are objectives and other are subjective. First among
them is to see presence of digits preference by contracting what we call the POPULATION
PYRAMID taking population on axis such
that one side male and on the other side female population is taken with ages
on y-axis. Ages may be taken in single year or 5 years interval. From
theoretical assumption if the population is closed to migration pyramid should
smooth triangle, however this is not the case as the mortality pattern every
age is not same and also the sex differential. The pyramid also reveals level
and pattern of fertility and mortality.

1. Whipple’s Index.

2. UN Secretariat Method.

3. Myer’s Index.

Three times the average of sex ratio differences
is then add to the two averages of the deviation of the age ratio from 100 to
complete the index. The resulting index is not exact and should by regarded as
order of magnitude rather than a precise measurement.

A method of blended
population suggested by MYER for obtaining the number of persons at ages ending
with digits 0 to 9 starting from 10 years onwards and then starting from 20
years onwards. The population at each digit in first case is given the weights
as 1, 2, 3 … 10 and population in second case is given the weights as 9, 9, 7…
0. Then the weighted average of these two populations has found and termed as
blended population.

**Over Statement of Ages of Children/ Infants:**

**Methods of Studying Error in Age Reporting:**

Subjective method of detecting miss-reporting of ages is
based on comparisons of data. Comparison is possible with in and between the
data of two series. Another comparison is possible with the last census or the
survey result. A group of persons who are in age group 5 to 90 in a particular
census will be 15 to 90 years of age after 10 years that is at second census
with possible reduction due to mortality keeping population close to migration.
A closed data examination reveals that there are consternation of persons at
ages, ending at (0 and 5) and even digits. This is attributed to wrong
recording of ages. Because this is not possible that births occur at such
interval as to have lesser number of person of ages ending at odd digits at a
particular time.

The indexes which are use in measuring it are:1. Whipple’s Index.

2. UN Secretariat Method.

3. Myer’s Index.

**WHIPPLE’S INDEX:**

Whipple’s Index
reflects the age heaping on multiple five that is terminal digit (0 and 5) with
in the age range from 23 to 62 years hence Whipple’s Index is defined as

Approximate 100 values of Whipple’s Index are
for low preference. Well it exceed 175 the quality of age data is very rough as
for UN standard. Maximum value of WI is 500 indicating that only zero and five
(0-5) ending digit has been recorded.

**UN SECRETARIAT METHOD:**

The method is
applied when we have data in 5 years age interval. In this method sex ratio and
age ratio for 5 years age group are found up to 70 years. In case of sex ratio
successively differences between one age group and the next age are found and
their average is taken without considering algebraic signs.

In case of age ratio for sex deviation from
100 are obtained and averaged of unrespectable of algebraic sign.

U.N.S. = 3 {Mean of |SR|} + Mean of |Average Ratio Male| + Mean of
|Average ratio of female|

**MYER’S INDEX:**

The range for the two populations must be kept same. The
data below age 10 and after age 80 is usually not consider for forming Blended
population (BP) as the accuracy of information is highly questionable.

The blended population of digit 9 is made the unit of
comparison and the ratio is found. A ratio of 1 shows low preference for the
digit and the ratio of more than 1 show more preference.

Another way of finding the digital preference is
to measure accuracy of the total BP of each digit. A extend of preference is
indicated by the preference deviation from 10%. In order to measure the total
amount of error in age reporting for a population Myer drive the preference
which is simply a sum of absolute deviation from 10%. In the absence of error
its index is zero and maximum value is 180.
MYERS INDEX DEVIATION POPULATION (MIDP)

MIDP= ∑ |column (10 –
11)|

## No comments:

## Post a Comment