Ballpark figure

[countrykid]

I know what it means when someone says "just give me a "ballpark figure" meaning maybe a rough estimate, but where does this stem from. The use of ballpark sounds american.

[Clanad]

You're right, it is an Americanism...
"Ballpark" has been used to mean a broad area of approximation or similarity, or a range within which comparison is possible; this usage OED dates to 1960. Another meaning, "sphere of activity or influence", is cited in 1963. "In the (right) ballpark", meaning "within reasonable bounds" dates to 1968. A "ballpark figure" or "ballpark estimate", one that is reasonably accurate, dates to 1967. (Source: The New Dickson Baseball Dictionary).
Although I'm not familiar with the size of an English Cricket Pitch, I think the American baseball park is considerably larger. The distance between bases is 90 feet but the distance from home plate to the left field wall is near 400 feet in most Pro ball parks. So, anything within that park occupies only a small part of a very large piece of real estate indeed. The phrase, as you've surmised, is a rough estimate or very generalized approximation...

[jno]

the impression I've always had is that it is a rough guess but not a totally crazy one - which would be so wild it isn't even in the ballpark. Clanad, cricket grounds are as big as a piece of string, so to speak - apart from a 22-yard pitch for bowling/running on, and I think a designated circle for fielders in the one-day format of the game, they can be almost any size at all. Some are famous for being so small that batsmen can easily hit the ball over the boundary, others so big that fielders are chasing the ball all day.

[VS Prasad]

1. (idiomatic) colloquial (USA) An educated guess or estimation within acceptable bounds.
"No more stalling. Give me a ballpark figure of our projected losses".
2.A guestimate.

http://en.wiktionary.org/wiki/Ballpark_figure
http://www.usingenglish.com/reference/idioms/b allpark+figure.html

At first, people described rough numerical estimates as "in the ballpark." An estimate that's in the ballpark is somewhere in the vicinity of the real value, as a baseball that a batter hits too far, but not beyond the bleachers, is still in the ballpark. More recently such approximations became known as ballpark figures.

http://www.phrases.org.uk/bulletin_board/12/me ssages/1119.html

http://idioms.thefreedictionary.com/ballpark+e stimate%2Ffigure

http://www.answers.com/topic/ballpark-figure

[countrykid]

Many thanks to all.