Before revision:  Since the collection of risk factors selected for investigation is large and highly correlated, we use dimension reduction methods , including the Least Absolute Shrinkage and Selection Operator (LASSO ) and prototype clustering , to perform the investigation.
After revision:  Since the collection of risk factors is large and highly correlated, we use dimension reduction methods , including the Least Absolute Shrinkage and Selection Operator (LASSO ) and prototype clustering , to perform the investigation.