Originally, much of the action around the speakeasies which proliferated during Prohibition, including having Laszlo involved with the mob. However, Russell T. Davies wanted to avoid the jazz music which would be predominant in such an environment, and so Helen Raynor came up with the Broadway and Hooverville settings instead.
Steven Moffat was originally going to write this serial. However, he was busy with Jekyll (2007), and so offered to write the Doctor-lite story Blink (2007) to compensate.
Helen Raynor drew inspiration from the Universal Pictures stable of monster movies, which were at their zenith during the Great Depression. Frankenstein (1931) was a main inspiration.
This is the first time since the Daleks' debut story that one of them has actually considered leaving their shell.