No. of Recommendations: 3
IMO, inflation adjustment is done for all purposes. Yes, it's used for generating the trend line, but looking at the real, inflation-adjusted stock price is also appropriate. Stock indexes on average increase by 6.5% (Siegel's constant) plus inflation. Eventually, when you sell your Berkshire stock, you spend that money on higher (inflation-adjusted) prices. So at the end of the day, the inflation-adjusted stock price is what really matters.
I guess to make my point another way. If you simply want to calculate P/B, you get the same answer if you inflation adjust both or neither so neither is easier but you definitely do not want to inflation adjust only one of them.