Description
Not all geostatistical layers provided in the Input geostatistical layers parameter have the same data source. For a fair model comparison, create all models from the same data source.
Solution
Use geostatistical layers that were created from the same data. The Source tab on the layer property page displays the data source of each geostatistical layer. If you use geostatistical layers from different data sources, the comparison may not be fair.