What was true a year ago or a decade ago may no longer be true. Optimism and pessimism feed on themselves. Naturally, blunders occur. Most of the time it is. This is why economists and models seem right more often than not.
Today is usually like yesterday, which was like the day before.
You too can make a credible forecast. Just read the newspapers and make a few minor adjustments to existing economic indicators. Because this is true, economic forecasts cluster together. The clustering also reflects herd behavior. There's less danger in being wrong with everyone else.