Figure:

Data source, preprocessing and analysis.

Abbreviations: DTC, Differentiated Thyroid Cancer; HRQOL, Health-related Quality of Life

Patients participated in up to 5 semi-structured interviews each. At the time of each interview, patients also completed several HRQOL assessments, including THYCA-QoL. Interviews were transcribed and qualitatively coded by trained researchers. Over 1000 runs using random splits of the dataset into training (80%) and test (20%) sets, ElasticNet models were used to predict HRQOL assessment summary scores from the assigned qualitative codes. The model was fitted using the training set and evaluated on the test set. Model parameters were selected using 5-fold cross validation. ElasticNet penalizes overly complex models; on each run, only a subset of features (qualitative codes) are included in the fitted model. The average R² value over 1000 runs was used to determine model accuracy. The most frequently selected features across the 1000 runs were recorded.