Do polygraph tests work?

Came across this interesting paper on polygraph tests.

Researchers examined historical cases of wrongful conviction -- where accused was found guilty, but later cleared using DNA evidence. The researchers looked at whether a polygraph test was used, and if so, whether the test got it wrong (said person was lying, when in fact the person was telling the truth).

What did they find? That "polygraphs produced unreliable conclusions in about 50 to 65 percent of the cases they examined".

More specifically, they found:

• Polygraph said "lying" (but person actually truthful): 46.8% (n = 59)

• Polygraph said "truthful" (and person indeed truthful): 31.7% (n = 40)

• Inconclusive: 8.7% (n = 11)

• Unknown / Unconfirmed: 12.7% (n = 16)

So for this universe (of wrongfully convicted persons), the polygraph test got it wrong much more than half the time.