How do I decide whether a bowl is a toucher or dead?

Toucher (laws 14 and 15): a bowl that touches the jack in its original course, even if it then goes into the ditch within the rink. It also becomes a toucher if, after stopping, it falls onto the jack before the next bowl is delivered (or within the 30 seconds after the last bowl of an end). It can't become a toucher by hitting a jack that is already in the ditch. It must be chalked as soon as it stops, or nominated if marking would disturb it; if neither happens before the next bowl stops, it is no longer a toucher.

Dead bowl (law 17): a non-toucher in the ditch; a non-toucher rebounding onto the rink off the bank, the jack or a toucher in the ditch; a bowl resting less than 14 metres from the centre of the mat line; a bowl moved by play completely outside the rink; or, in its original course, a bowl that crosses a side boundary on a bias that can't bring it back, or stops outside the side boundary (even touching a boundary jack).

Not dead: a bowl carried by a player inspecting the head; one that crosses a side boundary but finishes inside the rink; a toucher rebounding off the bank onto the rink; a toucher resting on the jack or another toucher in the ditch.

The skips (or singles opponents) decide first; you rule when they cannot agree, and your decision is final.