Smoothing parameter
= Smoothing parameter
{title2=$\lambda$}
A smoothing parameter controls the amount of averaging or regularization in a fitted function. Increasing the penalty multiplier $\lambda$ in a <cubic smoothing spline> discourages curvature and generally reduces <effective degrees of freedom>. Increasing a <smoothing bandwidth> enlarges local averaging neighbourhoods. Software may use a monotone transformed parameter such as `spar`, so its numerical value should not be confused with the raw penalty multiplier.