9.1 Definitions of a Study and of a Model
Study: A study describes the data on progression from one state to another state. This information is available in the literature and is usually found as incident counts from a given initial population count that reaches a state by the end of the study duration. Alternatively, study results can be reported in functional form.
Model: A specification of the disease progression created by the user within the system. The progression is defined as a set of states and processes, and of transitions between these states. Transitions hold transition probabilities that describe transition from one state to another.
Since both studies and models describe a disease process, they are bundled together in this system. The system distinguishes between study and model using the Study Length field. A model has a duration of 0, while a study has a duration greater than 0.
Studies contain data regarding part of the disease model studied in the study, and are generally much simpler in structure than models. Actually they are restricted to a single sub-process. Studies are related to estimation projects, where they are used to provide information to estimate unknown model parameters. These parameters can then be calculated during an estimation process. Models with known transition probabilities can be used in simulation projects.
9.2 Working with Studies/Models
9.2.1 Creating a Study/Model
1. From the main window, click the 'Study/Model' on the left navigation pane.