Why Wall Street Strategists Always Seem Bullish

 | Dec 21, 2016 12:56AM ET

Let us divide those writing about forecasts into three camps:

  1. Those who make specific forecasts, sometimes required as part of their job;
  2. Those who criticize, but do not forecast;
  3. Those who make dramatic, non-consensus forecasts to get attention.

I plan a few more posts on this theme, but today I want to consider group 2. If you are seeking attention, it is easy to write a popular article about forecasting. Start with the viewpoint that the experts are dumb and that the average investor can do better. People love to be smarter than experts. Surveys show that 90% of all people are above average in intelligence! Well, maybe not 90%, but far more than half . They are very receptive to this approach.

Taking this easy target, the His report got a million page views and even more publicity in the sequel. I see plenty of bias and errors in his work, but let me start with the most colorful claim:

Now imagine having a coin calibrated to show “positive” 2/3 of the time, and “negative” 1/3 of the time. Flipping this coin would therefore outperform a Wall Street strategist!

This is an oft-cited concept. If the market declines 1/3 of the time (actual performance is a bit better, but we’ll go with the author’s numbers) and no Wall Street strategist forecasts lower stocks, supposedly that is proof that the experts are too bullish.

The author has quite obviously never had to forecast anything, and his math is seriously flawed. Suppose you merely forecast an up market. You will be correct 2/3 of the time. He uses his magical coin. 2/3 of the time it forecasts “up” and it is correct on 2/3 of those occasions. 4/9 in the win column. The coin forecasts “down” on 1/3 of the years, and it is correct 1/3 of the time. That is another 1/9 in the win column. So less than 56% right instead of 2/3.

The author also produces this mystery chart: