>>overall effective tax rate<<
I have many awkward moments with clients concerning this calculation. In my software it means Line 61 total tax divided by Line 22 total income. That does not include non-taxable or deferred income, nor non-deductible or deferred expenses. Using AGI instead of Line 22 can bump it up. Allocating amounts to separate spouses is really confusing, and year-to-year comparisons are almost meaningless when bunching income and expenses. How do depreciation with recapture, AMT with credit, carryovers, and Lines 64-71 credits treated as payments change the "effective rate"? Not to mention shifting income or expenses to another entity.
On a national scale, the IRS can assemble some useful statistics with these numbers. In my opinion, there are too many variables to be of much value in individual tax planning. Most of my clients, however, disagree.