I had never seen an analysis like this. NPR analyzed graduation rates across the states. Not just the rates, but how those rates are calculated. There are some very interesting differences between states. For example, Colorado offers two types of graduation diplomas. Texas doesn’t classify hundreds of thousands of kids who “leave” K-12 as being dropouts, and offers 11 types of diplomas. Colorado is ranked 36th in the nation for graduation rates, Texas is 2nd, yet the standardized test scores are virtually identical.
These are only small examples. All across the country are many differences which make it virtually impossible to compare one state to another, or in some cases, even districts within a state.
Here is a link to the article which dives into the complexities of calculating graduation rates.