In a laboratory study on the effects of noise on cognitive performance and well-being, a standardised concentration-performance test (KLT-R) was applied as one of two cognitive tasks. The KLT-R consists of small arithmetic problems. Solving the problems requires concentration as well as memorization of instruction and interim results.The study was carried out in a repeated measurement design, with an interval of approximately one week between the first and the second point of measurement (T1 and T2). Each participant (N = 68) worked on the test once under a silent condition and once under a condition with one of three pre-recorded experimental sounds (checkout at fashion retailer, multi-space office, construction site). In total, results showed on average a significant increase of correctly finished items between T1 and T2, but only a small difference between the silent and the sound condition. However, the amount of the increase between T1 and T2 varied with the presentation order of the acoustical conditions and slightly between the three groups with different experimental sounds.Although a small degree of influence of noise was observed in the concentration test, critical issues arose whether this test is appropriate for studies with a repeated measurement design, especially with a very ambitious group of participants, who apparently found ways to optimise their performance between both measurement points.

The complete article is published in the Journal "Applied Acoustics" (2025).