About DF search

The single parameter to be set by the user is the number of degrees of freedom (DF) to employ. The DF parameter controls how closely the curve (spline) fits the input data. It is necessary to ensure that the curve is not over-fitting or under-fitting the data.
This parameter is dependent on the study design (number of time-points, sampling rate, time-scale of the function of time under study) and therefore only needs to be selected once per dataset.

Some indications based on simulated data and diverse datasets can guide the selection of DF:

While it does not seem possible to fully automate the selection of the number of degrees of freedom, DF Search implements visualisation approaches to assist in the selection of an adequate DF to apply across all variables for a given dataset.

Eigen-trajectories estimation

Auto-Fit

Parameter Evolution

Plot Fit

Missing Value