ABSTRACT
Sheep will continue to jump over the spot where their predecessors jumped even when the original obstacle the first sheep jumped over is no longer there. Dated data affect people the same way. Dated data can be historical memories-streetcars, horses, buggies-that if much older some of us experienced (and if younger may have seen in the movies). They can also be precepts, directives, instructions passed on to us by our elders that may be valid and relevant, or may direct us to jump over non-existent obstacles. It is up to us to examine our maps to see if they are hopelessly out of date for our purposes, or still useful.
