What is the percent deviance explained in relation to genera

What is the percent deviance explained in relation to general additive models?

Solution

The parametric estimates are listed with tests of significance against a null of zero.  A summary of the smoothed terms are listed next, which here is only s(elev).  Reported statistics include the estimated degrees of freedom (edf) and a test of whether the smoothed function significantly reduces model deviance.  Finally, a pseudo-R2 is available using deviance explained (here 32.5%); this statistic is just 1 – (residual deviance/null deviance).