When Writing and Speaking are Off-Base

[Mark Stellmack]

An increasingly common phrasing that I see and hear when students are writing and speaking goes something like this:

"We did an experiment that was based off of a previous experiment."

"Based off of"?  Huh?  The expression is "based on", not "based off of"!  An object is placed on a base, and the base serves as a foundation for what rests on it.  So, one thing is "based on" another, either physically or conceptually.  "Idea A is based ON idea B."

How is something "based off of" something else?  When "A is based off of B", is B supposed to be like the home base and A branches off of it in some way?  In what physical situation is something "based off of" something else?  Is a dramatic reenactment "based off of a true story"?  No, it's "based ON a true story"!  When the Beatles wrote "Paperback Writer", was the story "based off of a novel by a man named Lear"?  No!  "It's based ON a novel by a man named Lear"!

I have a feeling that if I tried to explain this to students, they would say that it had no "affect" on them, but that's another story.