Welcome to our work stream on guidance & training materials about **improving rigour** in legislative drafting, by taking **non-tech** lessons from modern logic & computing. @[osf](xs92z) We see this as continuing the progress made when the switch from **"shall" to "must"** brought home the fact that legislative drafters across the Commonwealth had been using "shall" very loosely to cover both "must" and "is"/"means" provisions ("**normative**" and "**constitutive**" in the jargon). It is useful to analyse our use of "must", "must not" and "may", particularly in terms of "if-then-**else**". Drafters need to be satisfied that readers will be clear enough, in a "**must**" provision, about the links (express or implied) to what is meant to happen - if the **conditions** are **not met** for the "must" to apply - usually just that the person **does not have to** do the act, but sometimes that they must not do it; and - if the person **does not do** what they "must" - some sort of **sanction**, possibly a criminal offence, but also possibly just that **a legal effect does not follow** (e.g. if an enforcement notice does not contain info that it "must" contain, then the person served with it does not have to comply - is that clear from the draft?) The rigour that has been brought to "must" also needs to be applied to "**may**". Legislative drafters currently use "may" in several different ways, and the links to related provisions (for "else" cases) are not always as clear as they could be - **permission** - where an exception is being made to an obligation or prohibition (because otherwise we "*may*" do anything without needing a law to say so) - is there a **clear enough link** to the obligation or prohibition? - **power** - where there is no need for permission, but if the person does what they "may" then it will impose some legal effect on someone else (as in "an aggrieved person *may* request a review") is there a **clear enough link** to the triggered effect (& is the "may" really useful)? - **possibility** - where there is no normative intent, and "might" or "is" would serve better - commonly in "as the case *may* be" (which is now discouraged), or "any person who *may* be on the premises must wear a mask, regardless of what the status of the premises *may* be". We will post more materials here as they become available - meanwhile we have our **plan** and a draft of **training** notes. @[osf](nbrws) @[osf](vcmhp)