Grammar Police

Hyphens:

• Compound adjectives: Use a hyphen when a phrase (adjective-noun or noun-noun pair) is being used as a single adjective (e.g., large-scale, visible-light). I.e., hyphenate compound adjectives. The whole point of the rule is to give the reader a clear signal of where that first word belongs (i.e. not in the previous phrase).
• Adverb-adjective pairs: Don’t use a hyphen when an adverb just defines an adjective as usual (e.g., well understood, rapidly evolving, typically warm, vertically propagating, mechanically driven, spatially resolved). I.e., don't hyphenate adverb-adjective pairs.
• Use a hyphen between numbers and units when they are being used as a single modifier (e.g., the 5-mbar level).

Commas:

• Use the Oxford comma.
• i.e. and e.g. are always preceded by punctuation, but only in American English are they followed by a comma.
• ‘Which' must always be prefaced by a comma. Otherwise use 'that.’
• Commas separate full subordinate clauses (i.e., and IT prompted…); comma after ‘Hence’

Flotsam and Jetsam

• 'biannual' is twice a year; 'biennial’ is every 2 years.

• Cruellest, modelling, travelling – doubled consonants in British English but not American English. Focussed (BE) and focused (AE) both acceptable.

• Split infinitives (“to better understand”, “to boldly go”) are now generally acceptable.

• Disc is British, disk is American, but use disc for optical storage (compact discs) and disk for magnetic (hard disk).

• Program for computer programs, programme otherwise.

• Adverbs are acceptable before or after a verb (cooled dramatically or dramatically cooled).

• Principal – adjective meaning ‘most important’ or the principal of an organisation; principle – noun meaning ‘fundamental basis’. PCA is a Principal Component Analysis.

• ‘Compare to’ when implying resemblance, ‘compare with’ to point out differences.