Predictions are just that, a persons best bet of what might happen, not what will happen. Until the event actually comes to past, a prediction will always simply be an expression, an ideal of what might or could possibly be.
In 1938 British Prime Minister Neville Chamberlain predicted there would be "peace in our time".
Boy, was he wrong.
A good prediction will be based on observing what is going on around you and estimating the various outcomes and then choosing the most likely. Anything else is random guessing.