Posted by TheFallen on November 08, 2002
In Reply to: Please help solve an argument... posted by anthony austin on November 08, 2002
: Is the correct expression...
: "Off your own back...:
: "Off your own bat..."
From the Concise Version of the OED:-
"Off one's own bat (Brit.) Unprompted, unaided."
A number of idioms get changed through mishearing, misunderstanding, or a desire to be correct leading to getting the idiom wrong. A recent classic example is the gradual evolution of "If you think that, you've got another think coming" (which is the original and corrct version), to "If you think that, you've got another thing coming", which is now possibly more prevalent in English usage, especially in American English. The interesting thing is that it seems to be prevalence that eventually defines what is correct.
There's an archive on thing/think coming linked to below, which coincidentally enough came to be discussed as the result of another office argument.