It was another bloody week in the stock market (S&P 500 Index (SPY) dropped -3.1%), and any half-glass full data was interpreted as half-empty. The week was epitomized by a Citigroup report entitled “World Economy Trapped in a Death Spiral.” A sluggish monthly jobs report on Friday, which registered a less than anticipated addition of 151,000 jobs, painted a weakening employment picture. Professional social media site LinkedIn Corp. (LNKD) added fuel to the fire with a soft profit forecast, which resulted in the stock getting almost chopped in half (-44%)…in a single day (ouch).

It’s funny how quickly the headlines can change – just one week ago, the Dow Jones Industrial Index (DIA) catapulted higher by almost +400 points in a single day and we were reading about soaring stocks.

Coherently digesting the avalanche of diverging and schizophrenic headlines is like attempting to analyze a windstorm through a microscope. A microscope is perfect for looking at a single static item up close, but a telescope is much better suited for analyzing a broader set of data. With a telescope, you are better equipped to look farther out on the horizon, to anticipate what trends are coming next. The same principle applies to investing. Short-term traders and speculators are great at using a short-term microscope to evaluate one shiny, attention-grabbing sample every day. The investment conclusion, however, changes the following day, when a different attention-grabbing headline is analyzed to a different conclusion. As Mark Twain noted, “If you don’t read the newspaper, you are uninformed.If you do read the newspaper, you are misinformed.”

Short-termism is an insidious disease that will slowly erode short-run performance and if not controlled will destroy long-run results as well. This is not a heretic concept. Some very successful investors have preached this idea in many ways. Here are a few of them: