From Stanley Woo - Quality Assurance:

"Ok, I got a PM from fuzzy_shortyking about this, so I thought I'd scour the old BioWare programmer list for people who'd worked on NWN. After three or four attempts, I managed to snag the inimitable Brenon "Kilimanjaro" Holmes, who was able to give me the low-down on Detect Mode and all of its secret, inner workings. We tried to involve Craig "Uncanny Frankie Valli" Welburn in the conversation, but the network gods we worship were not appeased by our offering of stale Doritos and croissants. Here's the breakdown I received from Mr. Holmes, which is probably about as "official" as any info gets. He went through old NWN code and everything!

Passive (default) modeEdit

• Trap detection radius: 5ft
• Trap detection rate: 6 seconds (every round)
• Trap detection roll: d20
• Spot/Listen roll: d10

Active (Detect) modeEdit

• Trap detection radius: 10ft
• Trap detection rate: 3 seconds (twice per round)
• Trap detection roll: d20
• Spot/Listen roll: d20

Stealth checksEdit

• Player detects stealth: 5 times per second
• Player rolls for hide/move silently/spot/listen: 6 seconds
• NPC detects stealth: 4 seconds
• NPC rolls for hide/move silently/spot/listen: 6 seconds

Hopefully, that will clear something up."