Using data from SHR. Multivariate analysis and propensity score matching will be used for analysis. Adjustments is made for all known and possible confounders such as age (above or below median age), gender, primary or recurrent hernia, emergent or electively operated, ASA class (≤2/>2),mesh weight (light (≤50g/m2) or heavy (> 50g/m2)), resident or consultant surgeon, annual surgeon volume (≤25/>25), hernia anatomy (femoral/medial/lateral- combined hernias considered as lateral), per or postoperative complication yes/no (hematoma, severe pain, infection and other complications), handling of the hernia sac (divided excised or invaginated) and type of hospital and others.