To promote knowledge in rock mass classification methods, a short course was arranged in research tunnels beneath Aalto University in Espoo, Finland. After the course, the participants had a short (45+45 min) hands-on tunnel mapping exercise where they logged 12 core boxes and one 10 m tunnel wall section. The attendees were asked to submit their mapping sheets for a post-study. The objective of the study was to discover which parameters show most scatter and to develop suggestions to improve the teaching methods. Statistical analysis of the data was carried out and RQD parameter was analyzed in more detail as it had the largest amount of data. Insufficient logging time may be one of the causes for the lack of data for other parameters. Significant scatter was observed in the RQD parameter and the comparison between inexperienced and experienced mappers show no clear difference. The teaching arrangements and problems faced are stated and recommendations on how to improve the situation are presented.