Statistics that accurately represent the evolution of tourism activity are needed for tourism research and planning. Monthly accommodation statistics provided by the Chilean Statistical Institute show a negative trend despite considerable growth in the number of foreign visitors. This paper proposes a methodology to create sample weights to overcome statistics inaccuracy caused, as in the case of Chilean tourism statistics, by the use of a non-random sample with serious attrition bias. The benefits of the methodology are discussed, highlighting their relevance to a broader range of applications where tourism statistics are questionable or demonstrably inaccurate.