If anyone needed proof that a course in statistical inference is necessary for journalists, it was provided by this report in the newspaper Mail Today on incidents of communal violence between 2011 and 2013 (written by Abhishek Bhalla).
There was even a tweet:
The main claim in the article was:
The Congress has always found it convenient to attack the BJP for spreading communal hatred in the country, but the Union Home Ministry’s latest data on communal violence is embarrassing for the Grand Old Party.
A look at the Union Home Ministry’s data reveals that there is not much difference between the two major national parties when it comes to the law and order situation in their states.
Exhibit A is this chart:
Of course the total number of incidents of communal violence in a state tells you nothing very interesting about the level of communal violence. A larger state will have more of everything than a smaller one. What you need is the number of communal violence incidents per unit of population.
Once you factor in population the picture changes quite dramatically. The four Congress Party-ruled states had 636 communal incidents between 2011 and 2013. These states had a population of 299 million according to the 2011 census. The three Bharatiya Janata Party (BJP)-ruled states had 641 incidents in the same period and a population of 194 million. We exclude the 38 incidents that fall under “other states” since we don’t know which those states are.
The conclusion is pretty straightforward. Congress Party-ruled states had 2.13 communal incidents per million population, while BJP-ruled states had 3.3. The rate of communal violence in BJP-ruled states is therefore 55% higher than in Congress-ruled states.
Exactly the opposite of what the article originally claimed.