Options are one factor that affects a stock price. other factors are news about a company and overall market sentiment. For example, if a stock posts good earnings and a robust outlook for the next quarter, but the DOW is down 300 points because of oil falling, then it will be difficult for the stock to make gains. The same holds true for max pain. Option writers will establish a hedge in order to remain delta neutral. But that is only one factor influencing the stock price. Therefore max pain is not always accurate. Simply look back at the first 8 or 9 weeks of 2016. Oil prices drove the market to wild swings. If oil was down, then it was assumed that oil companies and nations who depend on oil profits could not make payments on their debt. That dorve down the financial stocks as banks often provided the loans. The whole market traded lower.
I think a better question is to ask is does the theory make sense? The function of a market maker is to create a market for financial instruments. In order to be timely the MM must fulfill orders in very short amount of time. That means the MM is not shopping for seller when you enter a option buy order. Instead, they'll simply write the option themselves. The MM is taking on a position by selling the option. He is taking on risk. To offset that risk he'll purchase the stock. In the easiest to understand terms, think of a writing an uncovered call. Would you take on that risk? Instead you'd sell options against a position you already have or at least create. The same goes for the MM. The algorithms the MM use to remain neutral are clearly more complex than that, but you get the idea. That theory seems logical. It is supported by Neil Pearson, Professor Financial Markets and Options. Please see his opinion in the article seekingalpha.com/article/270466-digging-deeper-options-expert-discusses-pinning-max-pain-and-apple-part-two
What does this mean for you when looking at the option data on this website? First, it means that options are one factor of many affecting the stock price. It is not always going to be correct. It will often be wrong. Second, the more open contracts for a stock means a larger hedge position and therefore more influence. I generally only pay attention when there's 50,000 open contracts for a weekly expiration. Third, use the open interest walls for more accuracy. The OI walls give a range instead of a single value. It's more difficult to pick a single value for a close than a range, so the chance of the OI walls being correct is greater. Travis Sago shares this opinion and you can read about it on his blog
How can you use the information provided on this website? Based on the three points above you need to look for stocks that have a high number of open contracts and that are trading outside their open interest walls. It helps if the stock is relatively quiet with no news or other factors greatly influencing the stock price. I'm working on enhancing the screener to provide date on stocks that fit that profile.