Active investing, look laterally in the same industry and trade up in quality

Value investing is never passive.  Like other strategies, it is also an active process employing knowledge, skills and using various tools.

One approach to finding a cheap (value) stock starts with a bottom up approach.

Having discover and own a stock in a particular sector, one can also look laterally to analyse other firms in the same industry.

Are these also cheap, and for the same reasons?  

You may decide that one of these other companies is a better investment than your initial purchase.

Perhaps, it is a higher quality company, with better profit margins or lower debt levels.

If so, you may trade up in quality, provided that you can still take advantage of the depressed status of the industry.