Style error: MHRA author-date
Actual output (from "Create Bibliography from Item…"):
Propertius, Elegies, George P. Goold (ed.), trans. by George P. Goold (Cambridge, MA: Harvard University Press, 1990)
Expected:
Propertius, Elegies, ed. and trans. by George P. Goold (Cambridge, MA: Harvard University Press, 1990)
or
Propertius, Elegies, ed. & trans. by George P. Goold (Cambridge, MA: Harvard University Press, 1990)
(The latter is what is rendered using modern-humanities-research-association.csl. There is no example for "ed. and trans." in the MHRA guide, http://www.mhra.org.uk/Publications/Books/StyleGuide/StyleGuideV3_1.pdf, but since ", and" is recommended for separating authors while "&" and other forms are rejected [p. 77], I would expect "ed. and trans." to be the preferred form.)
Propertius, Elegies, George P. Goold (ed.), trans. by George P. Goold (Cambridge, MA: Harvard University Press, 1990)
Expected:
Propertius, Elegies, ed. and trans. by George P. Goold (Cambridge, MA: Harvard University Press, 1990)
or
Propertius, Elegies, ed. & trans. by George P. Goold (Cambridge, MA: Harvard University Press, 1990)
(The latter is what is rendered using modern-humanities-research-association.csl. There is no example for "ed. and trans." in the MHRA guide, http://www.mhra.org.uk/Publications/Books/StyleGuide/StyleGuideV3_1.pdf, but since ", and" is recommended for separating authors while "&" and other forms are rejected [p. 77], I would expect "ed. and trans." to be the preferred form.)
"Editors should be referred to by the abbreviations ‘(ed.)’ or ‘(eds)’." (p. 77).
So I guess we'll want do do (ed. and trans.)?
Thought it's not entirely clear what this applies to. Examples show editors for a chapter citation and for books/anthologies with no author, but no case for an editor of an authored book. There using (ed.) would give you two pairs of parentheses right after each other.
Propertius, Elegies, George P. Goold (ed. and trans.) (Cambridge, MA: Harvard University Press, 1990)
I have no idea why the though it was a good idea to change the way editors are displayed in the author-date style (and then not spend any space/effort on actually describing the style).
I wrote to MHRA asking for clarification, let's see what they have to say.
If you want to change anything right now, I feel
Propertius, Elegies, George P. Goold (ed. and trans.) (Cambridge, MA: Harvard University Press, 1990)
looks less odd (though not much) than
Propertius, Elegies, George P. Goold (ed.), trans. by George P. Goold (Cambridge, MA: Harvard University Press, 1990)
This shows that the (ed.) only refers to editors as primary creators, so this now follows the format nickbart initially suggested, i.e.
Propertius, Elegies, ed. and trans. by George P. Goold (Cambridge, MA: Harvard University Press, 1990)
The manual (v3.2, 2015) is silent on reports, but gives instructions and examples for books that are part of a numbered series (p. 61, and examples viii, x, xv on p. 59 f.). Adopting this for reports, the expected output with modern-humanities-research-association-author-date.csl should be, e.g.:
World Bank. 1998. Assessing Aid: What Works, What Doesn’t and Why, Policy Research Report, 18295 (Washington, DC: World Bank)
Also, with "Report" items, modern-humanities-research-association.csl renders the complete date (incl. day and month) whereas modern-humanities-research-association-author-date.csl renders the year only.
Since it seems many users are using the report type for publications like press releases, UN, EU, … documents and others where the exact date is relevant, I would suggest that modern-humanities-research-association-author-date.csl should render day and month, too; separate from the year of course. An example from the manual that shows how dates should appear in MHRA author-date (p. 78):
Friedland, Jonathan. 2002. ‘Across the Divide’, Guardian, 15 January, section G2, pp. 10–11
EDIT: Newspaper and magazine articles, too, are rendered with complete dates when using modern-humanities-research-association.csl, but with the year only when using modern-humanities-research-association-author-date.csl. Again, I suggest fixing modern-humanities-research-association-author-date.csl to render the complete date for both item types.