Collecting chance observations are an important element when monitoring large carnivore populations. They offer valuable information on the distribution of large carnivores. They often serve as indications on where to apply more robust, but also more work intensive methods to gain even more information. The interpretation and analysis of chance observations is difficult, as they do not originate from a standardised sampling design. An observation and its reporting depend on the presence of an observer and his/her willingness to report. These observers are usually not trained members of a network. This can lead to biases in the spatial distribution of reports and to a decrease in the reliability of the reports. To standardise the recording of chance observations, a common presentation and interpretation of the collected data has been agreed upon within the framework of the Alpine lynx monitoring: the so-called SCALP categories (SCALP: Status and Conservation of the Alpine Lynx Population). This standardisation allows for the comparison of monitoring data between different regions and countries. Moreover, the SCALP categories make it easier to interpret records and to make conclusions on the distribution based on those records. Collected date are classified according to their validity and their verification possibility into three categories:
- Category 1: „Hard facts“ such as lynx found dead, observations verified with photos, captured (young) animals and genetic analysis.
- Category 2: Verified reports from trained people such as kills of livestock and wild animals, tracks.
- Category 3: Kills, tracks and scats that are not verified, and signs that are not verifiable such as animal sounds or sight observations.
Nowadays, the classification into SCALP categories is not only used for lynx, but for various animal species.