In addition to the primary input data associated with each element, which affect the results of a STEM model directly, a further group of time-series inputs is provided for all of the main element types and also as a set of global inputs for the whole model. These inputs, which can be referenced in formulae and also in the definitions of derived results, are called User 1, User 2, …, and are located in the User Data dialog, which is accessed from the element icon menu (or, for global User Data, from the Data menu or by right-clicking on the background of a view). It is possible to rename User Data fields.
This facility allows you to calculate a primary input from several numbers or time series, and to use the same formula for all elements, effectively extending the input parameters of your model. STEM automatically uses year-zero values when these time-series user fields are referenced in a formula for a scalar field, such as a Cost.