Professor Piotroski decided to test his stock scanner to historical data, to compare the results vs. the ones reported for the period. This test finally resulted in what came to be known as Piotroski Score . The period in question was 1976 to 1996. It ended up giving 23% average return, annually. Validea reports, that by using a 20 stock portfolio size, that has ended giving 117.3% , bettering the market by 30.2%. Essentially, this score encompasses several accounting criteria with a binary score of 1 or 0. Each criterion, on fulfilling a condition is awarded either a 0 or a 1. A total of 9 points can be achieved. Stocks that clock scores between 0 and 2 are best weeded out of the portfolio. Stocks that score 7 to 9 are rated strong stocks.

Piotroski, a professor of accounts as part of his understanding the valuation of stocks wanted to understand if fundamental analysis had a role in selecting stocks. He shortlisted stocks with book/market ratios which were in the top 20%. He used their balance sheets and income statements; he used metrics like quality of earnings, leverage, operating cash flow etc. Eventually, he shortlisted 9 parameters under the heads of profitability, funding and efficiency, which was called F-score or the Piotroski score. A detailed understanding can be achieved by reading his paper Value Investing: The Use of Historical Financial Statement Information to Separate Winners from Losers (2000) provide link to paper.

The Nine Parameters of Piotroski Score

Let us take a look at the nine parameters of Piotroski score:

Profitability Parameters

Net Income: this is the total income of the company for the year – total expenses for year. Net income is calculated by taking revenues and adjusting for the cost of doing business, depreciation, interest, taxes and other expenses. Net income is often referred to as “the bottom line” since net income is listed at the bottom of the income statement.

Operating Cash Flow: A company generates revenue from its operations; this revenue minus taxes, interest paid, investment received and less dividend paid will give us the operating cash flow. A positive operating cash flow indicates the company has enough cash flow to fuel its growth.

Quality of Earnings: The portion of income a company earns thanks to its core activities rather than investments are called the quality of earnings. High quality earnings are a result of good sales and optimizing costs and usually recur over several reporting time frames. Investors look at this parameter to understand the source of income. High quality earnings are indicative of a thriving business with a good revenue model.

Return on Assets: A company’s annual earnings divided by the total assets will give us the Return of Assets or ROA. This parameter shows if the assets of the company are being employed effectively to generate income. That is assets are not being under-used , but optimally used. It is important that when we do comparative analysis of the ROA, it should be done, depending on the industry. Different industries have different ROA percentages.