There are lots of methods to calculate the fair value. The simplest one is to use average PE.

However, merely using average PE is not enough. Need to look at the fundamentals of the company as well for profitable investment

For glove stocks, even though their business model still remain the same..i would say that the oversupply of their rubber gloves, as well as increasing raw material cost & rapid falling of US$ have changed the fundamental of the affected rubber glove companies.. So looking at the fundamental of the companies is still important for profitable investment