Tania, the accuracy would be highly dependable on a variety of the factors presented in this discussion and the skill and experience of the Operator, so it is hard to say for sure.
I think it has the potential to be highly accurate and I’m hoping that those people interested in this topic may put up their successes, techniques and results as a kind of of testing group for accuracy.
A book similar to New Avatar Power, called Psychic Magic Power, was where I became aware of and first began to work with the pendulum. That was nearly 20 years ago. I’m getting old, lol!
In that book it says to first ask the pendulum to move in a direction to signify YES and then a direction for NO. After that, then you ask it a question or two that you already know the answer too, as a test. After this initial process you go on to ask your pre-prepared, well worded questions that enable a simple YES or NO answer.
It is easy to get hypnotized by the swing and lose focus and concentration, so that is another factor to consider. Starting off it may be better to keep the sessions short and sweet.