I am not sure if any official figures are available anywhere, but certainly the drop out rate is alarming high. When I was in the movement back in the 50s - 80s, the rate was roughly calculated to be in the region of 33%, with a slightly higher quotient for youths. However the passage of time has not been kind to the WTS, since the defection rate is increasing. Several on this board have in recent times indicated that the rate has in fact passed the dreaded 50% mark, meaning that more are leaving than staying.
I think that the more troublesome feature of this phenomenon to the WTS is not simply the overall numbers, but the quality of those leaving. Most of the best and the brightest have either savvied up to the intellectual dishonesty of the leadership, and are contemplating leaving, or have already left. Leaving behind a somnolent, amorphous tableaux of believers, either incapable of, or unable to, think for themselves. .
One thing that has escaped the understanding of the WT leadership is that an educated, articulate fellowship is an asset to its community. Naturally however this brings dissent, with the consequent need to formulate a theology based on varied but rational decisions.
Several religious groups have suceeded in accomodating these differing views, accepting the silence of definitive scriptures on a given abstraction. Various Baptist churches, for example, allow for either one, two or even three grounds for divorce, all argued cogently from Scripture. Another outstanding example is the broad spectrum of ideas spawned so profusely on this board with no consequent damage to the intellectual acumen of the members.
But the WTS, jealous of its claustrophobic hold that it has on its followers, lays down precisely defined dogma, even in the most trivial of circumstances, thus leaving no room for individualism. I believe that this intransigence on the part of the WTS leadership, along with its self serving rules imposed on the membership is responsible for such a high drop out rate.
Expect the WT leadership to get even more oppressive, and demanding, and expect a bunker like mentality to develop at the top. Expect the drop out rate to accelerate.
This can be seen even in the higher echelons of authority. Ray Franz once commented on the fact that most of the skilled wordsmiths who write WT literature, have dropped out, with the result that this literature today is often facile, circuitous, vacuous, and unencumbered with intelligent thought.
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