[2] SPECTRE was designed to overcome some limitations of existing software that affected Sims' research in the 1970s, by providing spectral analysis and also the ability to run long unrestricted distributed lags.
[3] The program was then expanded by Tom Doan, then of the Federal Reserve Bank of Minneapolis, who added ARIMA and VAR capabilities and went on to found the consulting firm that owns and distributes RATS software.
In the interactive mode, the user can run existing programs, or perform new tasks either by using menu-driven "wizards" or by typing in commands directly (or a combination of both approaches).
The menu-driven wizards automatically generate the corresponding commands, allowing users to interactively construct complete programs that can be saved and re-run later.
One advantage of RATS, as opposed to automated forecasting software, is that it is an actual programming language, which enables the user to design custom models, and change specifications.