Examples relate to a method, a computer program, an apparatus and a system for determining information related to an audience of an audio-visual content program. The method comprises monitoring at least a subset of the audience. The method further comprises determining the information related to the audience based on the monitored subset of the audience. The information related to the audience comprises measured metrics for the subset of the audience. The method further comprises determining at least one conversion factor based on a relationship between a property value measured within at least one previously monitored audience subsets and the corresponding property value of the previous audience. The at least one conversion factor indicates a relationship between a property measured within the monitored subset of the audience and at least one property of the audience. The method further comprises estimating the at least one property of the audience based on the at least one conversion factor.