`$P{<code>}` is replaced by the value the user gave for the parameter with that code, before the document was composed. The parameter itself is defined in the model; see [[Invantive Composition for Word/Modeller/Edit Model/Parameters|Parameters]]. The code in the marker is the code of the parameter, and nothing else: a parameter which does not exist is an error rather than an empty value, so that a typing mistake surfaces while the template is being validated instead of in the document. A parameter value is used in two places: - in the text, through `<invantive:value-of expression="$P{p_year}" />`, to print what the user answered; - in the `query` of a repetition, to limit the rows to what the user asked for. In a query the value is passed as a statement parameter rather than pasted in, so a value holding a quote is harmless.