To predict is to make a statement about the future.
The prediction doesn't have to be based on anything, but can be based on something(s).
If it is based on something(s) it doesn't have to be based on what somebody thinks that are fact(s), or it can be based on what somebody thinks that are fact(s).
Lottery prediction is also like that.
What is predicted might happen (come to be) or not.
If it does come to be, it might happen by what they call "Chance", if it doesn't it might also not happen by "Chance".
But predictions might be accurate or not accurate due to one or more things.
For repeated accurate lottery prediction we might want to take a look at and study the make-up of the lottery game (a lottery game) and repetition of patterns of characteristics of the game, the characteristics can be things that we make up and give to the game or things that it already has or both.
But as I said, people can predict in any way that they want to, that is why people's predictions are not always very often accurate, but also people can, but not very often win by chance.
About pre and post draws people blame them for their prediction(s) failure(s), when the real problem is their prediction technique (prediction logic).
About computer generated draws, some people also blame them for their prediction(s) failure(s), even if there are technical problems with the computer generated draws at it sometimes happens, that is not the real problem, what happens is that people don't study the patterns of the past winning numbers as a part of their prediction technique that is why people don't often win, that and using a bad prediction technique.
Once again, if you want to predict future winning numbers, you should study the past winning numbers and not so much the pre and post draws as those are not the past winning numbers, accurate lottery prediction should best be based on the history of the past winning numbers (frequency of patterns) and on the make-up of the game.
You can of course base your predictions on nothing or on anything that you want to, but you might not win very often and when you do it might be just by chance.
The lotteries can be blamed for failed predictions of course if they are not honest, that is if they don't conduct their drawings in a honest way, but don't misunderstand that, read what I said about pre and post draws.