Unlike the RTP, software providers are not legally required to share the variance of a slot. As such, there are a number of different tactics you can use to ascertain the payout frequency. Reading various slot forums is a great place to find out both the volatility of a slot as well as the general quality of it, while the paytable can give you a solid understanding how much a slot will payout for certain combinations. But, at the end of the day, the best way for you to work out the volatility of a slot is to play it and get a feel for it yourself.