Business ratios are used to compare similar companies within the same industry. RULE #1: DO NOT USE BUSINESS RATIOS TO COMPARE COMPANIES AGAINST EACH OTHER IF THEY ARE IN DIFFERENT INDUSTRIES.
Business ratios are not perfect, they have their respective flaws and it is important for value investors to understand the algorithms used with business ratios. It is also important to note that business ratios can be easily manipulated and result in misleading outcomes. More importantly, business ratios only reflect current information and not long-term trends. Think of business ratios as comparable to a doctor acquiring your vitals upon your medical visit. The vitals only reflect the ‘then and now’ status of your medical condition. They do not reflect your lifetime nor trending condition.
In effect, business ratios have a purpose, although limited. They are the best tools to compare similar companies within the same industry and typically the same market capitalization tier. Thus, a second rule to use with rule number one above; RULE #2: USE BUSINESS RATIOS TO COMPARE SIMILAR MARKET CAPITALIZATION COMPANIES WITHIN THE SAME INDUSTRY.
Because business ratios can be easily manipulated, it is important that users of business ratios have a full understanding of their respective formulas. RULE #3: BUSINESS RATIOS ARE NOT AN ABSOLUTE RESULT. They are merely indicators and that is all they are good for when interpreting their results.
Even with the above limitations, business ratios are beneficial to investors as they are the best method of comparing existing or potential investments. Their results are not perfect, but they can indeed provide adequate confidence when making pertinent decisions about a companies current financial status.