Ratios are comparison points for companies. They evaluate stocks within an industry. Likewise, they measure a company today against its historical numbers. In most cases, it is also important to understand the variables driving ratios as management has the flexibility to, at times, alter its strategy to make it's stock and company ratios more attractive. Generally, ratios are typically not used in isolation but rather in combination with other ratios. Having a good idea of the ratios in each of the four previously mentioned categories will give you a comprehensive view of the company from different angles and help you spot potential red flags.
