Psychological tests are often used to make important decisions about a patient’s trajectory. A high-quality test is characterized by norms that allow meaningful interpretation of the raw scores....Show morePsychological tests are often used to make important decisions about a patient’s trajectory. A high-quality test is characterized by norms that allow meaningful interpretation of the raw scores. With normed scores an individual’s performance can be evaluated properly by taking into account the influence of relevant individual characteristics, such as age, gender, education level or socio-economic status. From several norming techniques, regression-based norming has proven to be most efficient one and especially useful when including more than one demographical predictor variable. Recently, the R package GAMLSS has been proposed as a framework for this technique. It is an exhaustive family of flexible models that may fit a wide variety of empirical data. This research investigated the performance of GAMLSS compared to traditionally used approaches of multiple regression-based norming. Both techniques were applied to data of the Brief-Symptom Inventory, which was collected in a sample representative of the Dutch population (N = 1662). Age and gender were taken into account as normpredictors. The approaches showed very high correspondence, expect for a deviation of GAMLSS-based scores in the lower score ranges. None of the two approaches was able to properly capture the relationship between raw scores and age. GAMLSS-based norms did not outperform the regression-based approach. They can be considered equally suitable but in practice the complexity of the GAMLSS approach makes it less convenient. However, its flexibility could be advantageous when applied to tests that are heavily dependent on continuous norm predictors.Show less