# Fit Script

The fit script is probably the script you will use most often, as it performs the most common form of PK/PD analysis - finding parameter estimates for a PK/PD model given a set of observations.

See Fitting a Simple PopPK Model using PoPy or Fitting a Two Compartment PopPK Model for walk through examples.

## Main Sections of a Fit Script

- METHOD_OPTIONS

- PARALLEL

- DESCRIPTION

- FILE_PATHS

- DATA_FIELDS

- PREPROCESS

- EFFECTS

- MODEL_PARAMS

- STATES

- DERIVATIVES

- PREDICTIONS

- ODE_SOLVER

- FIT_METHODS

- COVARIANCE

- OUTPUT_SCRIPTS