It's not exactly a secret that on "Law & Order," they usually convict the perp. But every so often, they throw a wrench at viewers and have the defendant walk, and still more episodes end with McCoy et al finding the real killer, with a conviction implied but not shown. Thankfully, Matthew Belinkie at the aptly named Overthinking It has compiled the data and tracked court verdicts on the original "Law & Order," season by season:
You can find more charts — including one showing that "defendant killed or fled" is more common than a mistrial — here, and the full data are available in this spreadsheet. Now we just need a similar project on "Special Victims Unit" and we'll really be in business.