In the early 80’s Bob Brogan and Marc Chaikin developed the first adaptive band system, called Bomar Bands. (Bob + Marc), the first adaptive bands which let the data set the band width. They were designed to contain 85% of the price action over the latest 12 months (250 periods). That was a significant improvement to the former bands, as the width of the band grew or shrunk depending upon the market action.  The Bomar Bands consist of a center line and two price channels above and below it. If price tags the upper band and indicator action confirms it, no sell signal is generated. On the other hand, if price tags the upper band and indicator action does not confirm (that is, it diverges), we have a sell signal. 

Upper band contains 85 percent of data above the average for the past 250 periods

Middle band - 21-day moving average

Lower band contains 85 percent of data beneath the average for the past 250 periods

Bollinger Bands builds on these prior concepts of having bands built around price, but specifically, he seemed to take to the work of Chaikin and Brogan with their BOMAR Bands, and the work of Jim Yates:

• He based his calculations of how the bands move by using VOLATILITY to calculate where the bands are located.
• He used 2 STANDARD DEVIATIONS above and below the bands, which will contain (or explain) the odds of about 88 to 89% of price movement.