The father of value investing, Benjamin Graham, explained this...

The father of value investing, Benjamin Graham, explained this concept by saying that in the short run, the market is like a voting machine--tallying up which firms are popular and unpopular.

But in the long run, the market is like a weighing machine--assessing the substance of a company.

The message is clear: What matters in the long run is a company's actual underlying business performance and not the investing public's fickle opinion about its prospects in the short run.