Some called it fair value. Some use NTA, some use book value and some use PE ratio. But you must develop a view or price a stock. So that when market go below your price. You can start accumulating. When Markey goes beyond your price. You can hold or dispose. That’s basic buy low sell high but you got to know your price.
When everyone expected. It will happen but gradually. As for data from currencies to stocks. Some early sign of a major correction may come near. But the degree of the impact and harmful to which segment is yet to be known.