Question about Valuation

Hello All,

I am reading industry analysis. Can you please let me know why we should compare valuations of different industries while doing analysis about one stock? I read that such (= industry-wide) valuations will help us in determining the volatility of stock’s performance over the long-run and during different phases of the business cycle, which will be useful for long-term investing and short-term industry rotation based on the current economic environment.

I have no clue what this means. I would appreciate your response.

Thanks in advance.