The kinetics of light induced defect generation or the Staebler–Wronski effect have been investigated on device quality hydrogenated amorphous silicon films which were deposited by dc magnetron reactive sputtering. The total hydrogen content (CH) of the films, which varied from ∼10 to 28 at. %, had a strong influence on the defect generation. LowCH(10%–15%) films had a high initial density of defect states (∼7 to 10×1015cm−3) compared to the highCH(≥17 at. %) films with a density of ∼3×1015cm−3. However, light exposure increased the defect density more slowly on the lowCHfilms, such that after about 1 h of light exposure their defect density was lower. A high‐quality glow discharge produced film was also measured, and behaved similarly to the highCHsputtered films. The greater stability of the lowCHfilms was also reflected in a slower decrease of the electron photoconductivity relative to the other samples. For exposure times (t) up to 1000 h, the total density of defect states of the films increases as a power law: the highCHand glow discharge deposited films followt0.3andt0.32, respectively, whereas the lowCHfilm showst0.23at long times. The latter behavior is in sharp contrast with previous reports, and indicates that the degradation does not follow the Stutzmann theory or obeys it with a 100× smaller susceptibility to degradation.