In my experience, the use of “and/or” is becoming more common in legal writing these days. A document I reviewed recently had, on average, about three instances of “and/or” on each page. That’s prompted me to write this (inaugural) post about the difficulties with the expression and why you should avoid it.
Before I get into the difficulties with the expression, it’s worth noting that the use of the expression in legal writing has long been deprecated by judges:
- in 1942, Farwell J described it as an “unfortunate expression which I have not met before and which, I hope, I may never meet again”: Re Lewis  2 All ER 364 at 365;
- in 1943, Williams J described it as “an elliptical and embarrassing expression which endangers accuracy for the sake of brevity”: Fadden v Deputy Commissioner of Taxation (1943) 68 CLR 76 at 82;
- in 1944, Viscount Simon LC described it as a “bastard conjunction”: Bonitto v Fuerst Bros & Co Ltd  AC 75 at 82;
- in 1945, Gavan Duffy J referred to the “common and deplorable affection for the form ‘and/or’”: Millen v Grove  VLR 259 at 260;
- in 1950, Barry J said that the expression is “commonly an indication that the draftsman is not clear in his own mind about the matters with which he has to deal”: Looke v Parbury Henty & Co Pty Ltd  VLR 94 at 98; and
- in 1998, Burchett J described it as “a loose expression conveying a vague meaning”: In Re Moage Limited (1998) 153 ALR 711 at 716–717.
My favourite judicial admonition is undoubtedly the following passage from the (aptly named) Fowler J in Employers Mutual Liability Insurance Co of Wisconsin v Tollefsen 263 NW 376 (1935) at 377:
“It is manifest that we are confronted with the task of first construing ‘and/or,’ that befuddling, nameless thing, that Janus-faced verbal monstrosity, neither word nor phrase, the child of a brain of someone too lazy or too dull to express his precise meaning, or too dull to know what he did mean, now commonly used by lawyers in drafting legal documents, through carelessness or ignorance or as a cunning device to conceal rather than express meaning with view to furthering the interest of their clients. We have even observed the ‘thing’ in statutes, in the opinions of courts, and in statements in briefs of counsel, some learned and some not.”
When I criticise the use of “and/or”, I am sometimes met by a response along the following lines: “What’s the problem? I understand it just fine. ‘A and/or B’ means ‘A or B or both’. It’s a way of saving space.” So, what is the problem with “and/or”? I think there are three.
First, it can create ambiguity. For every writer that uses “and/or” correctly, there is a lazy writer who uses it when he or she meant to use a simple “or” or “and”. The reader (or the court, in a dispute about construction) must determine whether the writer intended to use “and/or” in its strict meaning, or whether they intended an “and” or an “or”. For some examples of the misuse of “and/or” in the cases, see Peter Butt, The Lawyer’s Style Guide (Hart, 2021) at 55.
Second, it is often unnecessary. That is because the word “or” has both an “exclusionary” and “non-exclusionary” meaning, which will usually be apparent from context. Consider two examples:
- Imagine a sign that says “No food or drink allowed on the premises.” No one could sensibly argue that the statement left open the possibility of bringing both food and drink on to the premises. The “or” here is being used in its “non-exclusionary” sense, and it includes “and”.
- If A alleges in a pleading that B “coerced or threatened” him, almost everyone would understand that to include three allegations: (i) B coerced A; (ii) B threatened A; and (iii) B coerced and threatened A. No sensible person would acquit B of the allegation if it turned out that B had both coerced and threatened A. Again, the “or” is being used in its “non-exclusionary” sense and includes “and”.
In other cases, the “or” will be used in its “exclusionary” sense and will not include “and”. This will usually be because there is some natural exclusivity between the two elements. Thus, if a statute authorises a judge to “impose a fine or imprisonment”, that is unlikely to be understood as permitting the imposition of a fine and imprisonment. If the writer has concerns that the sense in which he or she uses the word “or” may be misunderstood, the answer is to include “or both” or “but not both” at the end of the sentence. That makes the meaning of the sentence clear to the reader, whereas the use of “and/or” might leave open an argument that the reader intended something else (see the first problem discussed above).
There was some debate in R v Federal Steam Navigation Co Ltd  1 WLR 505 at 508–509, 520–522, and 523–524 as to whether the “non-exclusionary” meaning of “or” was a legitimate grammatical meaning of the word. But these days it is well accepted: see Bryan Garner, Garner’s Modern English Usage (OUP, 2016) at 50.
Third, when used in a series, “and/or” can give rise to an unwieldy number of possibilities. By my count, “A and/or B and/or C” creates seven possibilities:
- A, B, and C
- A alone
- B alone
- C alone
- A and B
- A and C
- B and C
The number of possibilities increases exponentially with each added “and/or”. For this reason, even if you don’t agree with my blanket ban on the use of “and/or”, be sure to avoid the use of “and/or” in lists containing more than two elements. For an example, see In Re Moage Limited (above), where Burchett J said that the use of “and/or” created “an almost endless series of additional and alternative allegations”.
For further reading, see Sir Robert Megarry, A New Miscellany-at-Law (Hart, 2005) ch 14 (“Andorandorand”).