That's what millions of NYT readers are asking after they saw the assertion:
"Republicans are concerned about the growth of entitlement programs, including Social Security and Medicare. Some, like Senator Tom Coburn of Oklahoma, support the idea of an alternative measure of inflation, known as the chain-weighted version of the, because they believe it is more accurate."
It is certainly possible that Senator Coburn and others supporting a lower cost of living adjustment actually believe that the alternative inflation index is more accurate, however it is also possible that they just want to cut benefits and couldn't care less whether the alternative index is more accurate or not. The NYT made a very strong assertion by saying these politicians are motivated by their beliefs about price indexes. It presents zero evidence to support this assertion.