- Geographical coverage :
There have generally been found a change in political area from one census to another . Before independence Burma , Pakistan, Bangle- Desh were very much a part of Indian population census . In 1951 princely states were included due to their merger with Indian Union .In this census Jammu and Kashmir although an integral part of the country was not counted for the purpose of population counting .It was only in 1961 census when Jammu and Kashmir although an integral part of the country was not counted for the purpose of population counting .It was only in 1961 census when Jammu and Kashmir was included in the process of population census . In addition to it because of a vast geographical area of the country most of the distant regions are not accessible. An attempt was made to cover such areas in 1961. Under these circumstances the population figures are not totally compared from one period to the other .
2. Definition of Age :
In different censuses the age was defined quite differently .By the year 1921 age was counted as per the year completed .From 1931 age was recorded as the age to the nearest birthday. It was further changed in 1951 and age to the nearest birthday. Since then same process is adopted . In addition to this illustration in this regards . In the past , age of the child was always expressed as in multiples of 5. Even for the marriage purposes the actual age was concealed . Old persons even at for the marriage purposes the actual age was concealed . Old persons even at this progressive world are not aware about their actual age.It looks quite surprising the most of the old persons do not know their actual date of birth even .They have generally been seen coinciding their date of birth with some incident such as war , famine , earth quake etc. Ladies too hide their age to themselves younger to their actual age .
3. Biased information :
At so many occasions it is experienced that the information is given and recorded by the recording personnel's with prejudiced mind . The information regarding insanity , dumbness , deafness is generally concealed .