Marrying out of caste – 1

This is the first in what is going to hopefully be a long series of posts on inter-caste marriages. As you might have figured out, I’ve stumbled upon a nice data set with lots of data on this topic (Hat tip: Nitin Pai and Rohit Pradhan), and there are some beautiful insights in the data.

The data is based on a National Family Health Survey which was conducted in 2005-06. The sample size of the survey itself was massive – close to a lakh respondents for the entire survey, and about 43,000 women who were surveyed on the inter-caste marriage question alone. So the survey, which was carried out in all states in India, asked “ever-married” women whether they were married to someone from the same caste, or to someone from a higher caste, or to someone from a lower caste. There was also some demographic data collected which leads to some interesting cross-tabs we can explore in either this post or one other of the series.

If there is one single piece of information that can summarise the survey, it is that the national average for the percentage of women who are married to someone of their own caste is 89%, and this number doesn’t vary by much across demographics or region or any other socio-economic indicators.

Of course, there are differences, and some regional differences are vast. For example, 97% of women surveyed in Tamil Nadu were married to someone from the same caste, while the corresponding figure in Punjab is only 80%. Figure 1 here shows the distribution across states of the percentage of women married to men of the same caste.



Different colours here represent different regions of India, and considering that the data in the above graph has been sorted by the value, the reasonably random distribution of colour in this graph (anyone notice a pattern anywhere?) shows that there is no real regional trend. But the inter-state differences represented in this graph are stark (80% to 97%). It raises the question regarding the homogeneity of castes and possibly differing definitions of castes in different states.

For example, some people might define caste as their “varna”, while some might go deeper into the family’s traditional occupation. Others might go further deeper – there is no end to the level you can reach in the caste hierarchy. Might it be possible that the stark regional differences can be explained by the varying definitions of caste?

Another interesting piece of data given is the percentage of women in each state married to either men of a higher or a lower caste. Now, in the interest of natural balance and matching, these two numbers ought to be equal (the paper notices a surprise that these two numbers are equal in most states – but there is no reason to be surprised). Actually we can create an “imbalance index” for each state – the difference between the percentage of women married to men of a higher caste and the percentage of women married to men of a lower caste.

A positive index indicates that women in the state prefer to “marry up” (men of higher caste) than “marry down”. It also indicates that in the absence of inter-state “trade” of marital partners, there will be large numbers of unmarried men of the lowest caste and women of the highest caste in that state! A negative index implies an excess of single men of the highest caste and single women of the lowest caste (both these calculations assume, of course, that the sex ratio is the same across castes). The second figure here plots this index across states. The  colouring scheme is the same.


This shows that there are states with massive imbalances – Maharashtra, for example will end up having a large number of single men of the lowest caste and single women of the highest caste unless they get “cleared” in “trade” with other states. Kerala has the opposite problem. It is interesting to notice that Punjab, which has the highest percentage of inter-caste marriages, also has a reasonably balanced market.

So should we explore if there exists a relationship between the proportion of women married to men of the same caste and how balanced the marriage market is in the state with respect to caste? The hypothesis, based on the example of Punjab in the above two graphs, is that the greater the incidence of inter-caste marriage in a state, the smaller the imbalance in terms of caste in the market. Let’s do a scatter plot which includes the above two bar plots and see for ourselves:


On the X axis we have the percentage of women married to men of the same caste. On the Y axis, we have the absolute value of the imbalance index (in other words, we don’t care which way it is imbalanced, we only want to know how imbalanced the caste dynamics in marriage is in each state). The blue line is the line of best fit. Notice that it slopes downward. In other words, the greater the number of same caste marriages, the smaller is the imbalance between women marrying above and below their own caste, which is interesting. Notice that Punjab sits all alone as an outlier at the bottom left of the above graph! Kerala is an outlier at the top left corner!

Now you might posit that if fewer people are available for inter-caste marriage, the difference between those “marrying up” and those “marrying down” is bound to be lower, since the sum is lower. However, if we normalise the index for each state by the proportion of inter-caste marriages in that state, the above graph will still look pretty much the same!

Caste and marriage are more complicated than we think!

10 thoughts on “Marrying out of caste – 1”

  1. The paper is actually more interesting! It has got variables like age, education, demographics etc. Off course as usual you made all these beautiful plots and all that but I think the paper in itself is highly informative.

    1. Only have access to this one dataset – we can estimate over period of time by looking at age of respondents – assuming that average age of marriage hasn’t changed much!

  2. I did not quite understand the need to do a scatter plot to arrive at the second conclusion. Is’nt it intuitive from the first piece of analysis that greater the number of same class marriages, smaller will be the imbalance index ?

    It would be quite interesting if you can combine this data with the crime records, literacy levels etc..

    Good work anyways 🙂

  3. The gross mistakes and unscientific findings of this survey are discussed in the comments of this post

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    ????? ?????? ??????????? ???? ???? ????????????2007-08 ?????????? ????????????? ???????????? 2265.????? ??????????? ???????? ??????????? -4205 .
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    Officials in the registration department claim that the number of such marriages has been on the rise with figures indicating that at least 10% of couples have opted for inter-religious marriages.

    According to the registration department, about 77,000 marriages were registered across the state under the Hindu Marriage Act 1955 during 2010-11. A total of 7,601 marriages were registered under the Special Marriage Act, indicating that 10% of the registered marriages were inter-religious.

  4. I have a bit of experience and knowledge in sampling studies and this study has followed no standard procedure nor given the numbers after taking arbitrary criterias as base for considering which constitutes intercaste marriage.
    The high percentage reported in certain states is mathematically not possible given the social structure and gross numerical variation between the groups.
    Lets take Goa

    The reservation for OBC s has been increased to 27% and SC remain at 2%. in exact proportion their population.There exists quiet a bit of christian communities in the OBC list.If we exclude the christians from the obc list the total% of hindu obc/sc will be around 20%.3/4th of those marriages in the community should be with castes in OC to reach a figure of 26% of intercaste marriages for the state among hindus.

    The study says that in goa 15.8%women marry lower than their caste and another12.6%marry men higher than their caste.
    Hindus are 73% of goa lets take it as 730 in numbers.270 in that are obcs and 20 are SC making OC 440.lets divide 730 by two into men and women.15.8% of 220 is 35 and 15.8% of 135 OBC is 21(though SC are just 2% to OBC 27% and there exists just 10 men out of total strength of 20 and hence 15.8% of obc women marrying someone less than their caste is not even remotely possible ,lets take it as correct for disproving the given facts in the study )

    OC women cannot marry anyone higher and hence this has to be entirely from OBC as SC numbers are very insignificant.12.6% of 135 is 16.12.6% of 10 SC women can be taken as 2.Totalling the number of women who have had intercaste marriages ,it comes to 35+21+16+2=74.The study figures if taken logaically for the two caste groupings which have caste higher than them,indicate SC men marrying double their number of women of higher caste to reach the figure of 74 which out of 365 is still around 20%.

    When the population of the three groups varies significantly ,there will be significant differences in the percentage of intercaste marriages in each group.

    Its surprising that the interreligious marriages is 1.3% in the same state which has the highest intercaste marriage ratio in the country irrespective of progressiveness and significant presence of christians which is more than 27%

    The arbitrary amalgamation of entire group of castes into just 3 castes oc/obc/sc has very little merit.The study makes tamilnadu having 3 castes with one caste around 65% and the other two around 15 and 4 excluding christians.Making 2/3 population of the state as a single caste group and considering all marriages between different castes under the same obc banner as same caste marriages will defenitely result in very low percentage irrespective of increased number of intercaste marriages.

  5. The percentage of people falling under SC is calculated in every census till date.

    Based on the Census figures published by the Registrar General of India, the Delimitation Commission prepared Paper I containing district-wise 2001 population data and the entitlement of seats for each district. The Commission also prepared Paper II indicating entitlement of seats for SC and ST in the Assembly/ Parliament and distribution of ST/SC seats in the districts. The total number of SC seats increased from 42 to 44, while the total number seats reserved for ST which was 3 as per 1976 delimitation got reduced to 2.

    I have no issues in accepting figures if they are obtained correctly but here the attempts and criteria are absolutely unscientific…/22728944.cms…

    govt figures for whole of India where one of the couples belongs to SC are

    2010– total 7148 tamilnadu- 2356
    2011– total 7617 tamilnadu – 2750

    The total SC population of kerala is less than 10% and the SC population of goa is less than 2% and the study which has taken just 3 groups for measuring intercaste marrriages (OC-SC,SC-BC,OC-BC)comes with impossible figures for goa where even if all SC marry others its still not possible to get the figures proclaimed by the study.Its strange that the study which has just 3 criterias doesnt give the split figures of how many are OC-BC,OC,SC,BC-SC etc

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