A method for assessing the result of a surface treatment carried out on a workpiece by particle jets, wherein The surface processed by particle jets is recorded in a spatially resolved manner by means of an optical measuring method and for the spatially resolved measuring points in each case a. a surface level and b. a value of a local gradient in relation to neighbouring measuring points is determined, wherein the detected surface level is compared with a target level expected for the untreated workpiece at the measuring location of the measuring point and a deviation is determined, and wherein the following steps are also carried out: (3.1) Identify those measuring points for which a. the surface level detected according to a. is above a level that is lower than the target level by a specified height threshold value, and also b. the gradient detected in accordance with b. falls below a specified gradient threshold, as measuring points not hit by a particle of the particle beam, (3.2) Dividing the number of measurement points identified in (3.1) as not hit by a particle of the particle beam by the total number of measurement points detected to determine a portion of the surface not hit by the particle beam. The surface processed by particle jets is recorded in a spatially resolved manner by means of an optical measuring method and for the spatially resolved measuring points in each case a. a surface level and b. a value of a local gradient in relation to neighbouring measuring points is determined, a. a surface level and b. a value of a local gradient in relation to neighbouring measuring points is determined, wherein the detected surface level is compared with a target level expected for the untreated workpiece at the measuring location of the measuring point and a deviation is determined, and wherein the following steps are also carried out: (3.1) Identify those measuring points for which a. the surface level detected according to a. is above a level that is lower than the target level by a specified height threshold value, and also b. the gradient detected in accordance with b. falls below a specified gradient threshold, as measuring points not hit by a particle of the particle beam, (3.2) Dividing the number of measurement points identified in (3.1) as not hit by a particle of the particle beam by the total number of measurement points detected to determine a portion of the surface not hit by the particle beam. (3.1) Identify those measuring points for which a. the surface level detected according to a. is above a level that is lower than the target level by a specified height threshold value, and also b. the gradient detected in accordance with b. falls below a specified gradient threshold, as measuring points not hit by a particle of the particle beam, a. the surface level detected according to a. is above a level that is lower than the target level by a specified height threshold value, and also b. the gradient detected in accordance with b. falls below a specified gradient threshold, as measuring points not hit by a particle of the particle beam, (3.2) Dividing the number of measurement points identified in (3.1) as not hit by a particle of the particle beam by the total number of measurement points detected to determine a portion of the surface not hit by the particle beam. <EOS>