RQ | 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!

DISCLAIMER: This is an archived post from the Indian National Interest blogroll. Views expressed are those of the blogger's and do not represent The Takshashila Institution’s view.