Pat Shingleton: "Confusing Percentages..."
In 2009, The American Meteorological Society noted that using percentages to forecast precipitation is a "confusing constant" for the general public. This prediction percentage was implemented in the late 60's with three psychological studies initiated by the University of Washington. The research respondents, college undergraduates, did not understand forecasts denoting percentages. Most of the participants believed a portion of an area or designated time period would receive a percentage of precipitation. When this system of forecasting was designed by the National Weather Service it outlined that within "a certain forecast area and during a forecast period "measurable" precipitation would be predicted by using a percentage."