What is the significance of <87 and >87 to the testing?
The symbols were tested through a well known survey method call Comprehension Estimation testing. This method has been used in many different countries and adopted by the International Organization for Standardization (ISO) because it produces consistent and reliable results. The instrument has the accepted threshold of greater than 87% as a measure of effectiveness. In other words, symbols that achieve a rating of greater than 87% are found to be comprehended by a vast majority. To learn more about how symbols were developed go to About Symbols. • Did all the symbols in this set receive scores >87? No. 17 symbols had at least one symbol that achieved scores greater than 87. When more than one symbol for the same referent achieved this threshold, the design team had options to select the strongest symbols for inclusion into the set. Most often, those turned out to be the symbols receiving the highest scores. Eleven symbols did not reach the threshold. These were generally referents wit
