Is it OK to use this expression in an academic text?
The given charts represent ball-park figures of mortality rates in European countries.
Is ball-park formal enough to be used in an academic context?
Is it OK to use this expression in an academic text?
The given charts represent ball-park figures of mortality rates in European countries.
Is ball-park formal enough to be used in an academic context?
There is no single authority to which one would turn to determine whether phrasing is "formal" enough for a situation; sometimes, even in an academic paper or a public address, colloquial phrasing is more communicative of tone, region, familiarity, and so forth. Whether it is acceptable is a judgment your audience makes.
Merriam-Webster does not mark the noun or adjective uses of ballpark to mean approximation or approximately correct as informal. It does mark the verb use, to make a rough estimate, as informal. So in Webster's eyes, the first two have become normalized for broad usage, but the latter has not.
The American Heritage Dictionary, which is historically a more conservative dictionary — it was created in part because Webster's Third International Dictionary was criticized as too permissive — marks the noun and adjective sense of ballpark meaning approximate not merely as informal, but as slang, suggesting it be avoided in serious writing.
For another consideration, the principal meaning of ballpark is a field used to play baseball, and as a metaphor it was first popularized in U.S. military slang. As you might expect, it is much more commonplace in American English compared to other varieties, borne out by the NGram. The OED marks the term as originally and chiefly U.S.
Given this, you might prefer ballpark as a more colorful term, or one familiar to U.S. audiences, but if you want to maintain a drier tone, synonyms like approximate, estimated, or on the order of might be suitable, with roughly, or simply around also possibilities.
If i read this in an academic article which i was reviewing for a scientific journal I suspect I might raise one or more of the following points.
1- Is it suitable for an international audience since it is more familiar in those places where baseball is played?
2- Why are you presenting an estimate based on a rough estimate rather than calculating a proper summary?
3- It seems rather informal in the context of the rest of the article.
I have no objection of course to them using informal language, it often makes the paper easier to read but if the rest is written in high academic speak it would bring the reader up short wondering where it came from.
I consider it somewhat informal. You could replace it with estimated or approximate.
If you need to stress that they are very inaccurate, you could use rough approximation or very rough approximation, but would need to change the structure of the sentence. I personally would equate ballpark with rough approximation.