14. Tables: creating, editing and using

TreeAge Pro can store indexed tables of numeric values that represent parameters in your model. Here are some basic facts about tables:

• Tables are typically created and stored with models in *.trex files. The following sections will show you how to create and edit values in a table.

• Every table has an index column and a value column. A table can have additional value columns (up to 512) and from one row of values up to tens of thousands of rows.

• Each row’s index value must be unique, but indexes are not required to be consecutive integers. TreeAge automatically numbers the value columns with integers (starts at 1).

• Tables can linearly interpolate values for missing indexes/rows, as well as interpolating across columns.

• Only numeric values (no variables or formulas) can be entered in a table.

• In Markov models, tables are often used to represent probabilities that vary over time (or other dimensions). You can use the index column to represent the time, and the values column to represent the changing probability. More details can be found in the section: Building and Analysing Cost Effectiveness Models.

• A table can represent a parameter’s empirical probability distribution to sample from during Monte Carlo simulation. You can refer to the section Sampling from tables for details on sampling from tables and other distribution types.

• Table Values can be loaded into a table in a variety of ways, including: paste tab-delimited text; edit via the Excel add-in; query an ODBC database; manually enter index-value combinations. These will be described in the sections which follow.