To the annoyance of some shareholders, Adelaide Brighton (ASX:ABC) shares are down a considerable 31% in the last month. Indeed the recent decline has arguably caused some bitterness for shareholders who have held through the 53% drop over twelve months.

Assuming nothing else has changed, a lower share price makes a stock more attractive to potential buyers. While the market sentiment towards a stock is very changeable, in the long run, the share price will tend to move in the same direction as earnings per share. So, on certain occasions, long term focussed investors try to take advantage of pessimistic expectations to buy shares at a better price. Perhaps the simplest way to get a read on investors' expectations of a business is to look at its Price to Earnings Ratio (PE Ratio). A high P/E implies that investors have high expectations of what a company can achieve compared to a company with a low P/E ratio.

Check out our latest analysis for Adelaide Brighton

How Does Adelaide Brighton's P/E Ratio Compare To Its Peers?

Adelaide Brighton's P/E of 28.38 indicates some degree of optimism towards the stock. The image below shows that Adelaide Brighton has a higher P/E than the average (20.4) P/E for companies in the basic materials industry.

Adelaide Brighton's P/E tells us that market participants think the company will perform better than its industry peers, going forward. Clearly the market expects growth, but it isn't guaranteed. So investors should always consider the P/E ratio alongside other factors, such as whether company directors have been buying shares.

How Growth Rates Impact P/E Ratios

If earnings fall then in the future the 'E' will be lower. That means unless the share price falls, the P/E will increase in a few years. A higher P/E should indicate the stock is expensive relative to others -- and that may encourage shareholders to sell.

Adelaide Brighton saw earnings per share decrease by 75% last year. And EPS is down 23% a year, over the last 5 years. This growth rate might warrant a below average P/E ratio.

Don't Forget: The P/E Does Not Account For Debt or Bank Deposits

The 'Price' in P/E reflects the market capitalization of the company. In other words, it does not consider any debt or cash that the company may have on the balance sheet. Hypothetically, a company could reduce its future P/E ratio by spending its cash (or taking on debt) to achieve higher earnings.

While growth expenditure doesn't always pay off, the point is that it is a good option to have; but one that the P/E ratio ignores.