User:SOTO/Forum Archive/The Panopticon/@comment-1293767-20151029072618/@comment-27920493-20161208212752

I am happy with these rules, but with the addition of having the same writer. Two episodes cannot be a two-parter if they have different writers.

If we go by these four rules (without a rule of having the same writer), AGMGTW and LKH aren't a two-parter as they have different directors and were produced separately, and also HS and HB aren't a two-parter as they too were produced separately (HS is block 6 and HB is block 8). If a rule of having the same writer is included, only TMA/TWF, UTL/BTF and TZI/TZI are two-parters in Series 9, TGWD and TWWL aren't a two-parter as they don't have the same writer.

Even though it wouldn't fit with the rules, I think "Utopia", TSOD and LOTTL should remain together as they are a confirmed three-parter by RTD himself.