There was an article in some mag, maybe Wildfowl where some Wisconsin college students did a project with spinners. It was very well thought out and covered all the angles(weather, type of birds, location, same hunters, guns shot etc) of a typiclal duck hunt.Study basically said that hunters who used spinner dekes had LESS wounded/crippled birds than hunters who didn't use them, so I guess they were saying spinners produce close, more consistant shots. Again this study was in Wisconsin, quite a bit north of us. Personally I use one till about 2nd week of December, and even then I use it mainly with alot of fog, and absolutly NEVER BLUEBIRD DAYS!!But like Monroe, I always have a jerk string, in fact I have 4 different strings now, for different set-ups/conditions, and late in the season, that thing is golden!!