In this study, we present a paper that analyzes the problems of creating digital models for predicting the Muslim population growth, which both individual scientists and such large research companies use in the creation of their works, papers and research. One of the most authoritative developers of digital models for predicting the Muslim population growth in the world is the researcher Houssain Kettani. His models are developed using advanced computational science and engineering techniques and include high-performance computational algorithms, data methodology, and number theory. Despite the objectivity of this kind of research and the popularity of their use in political, analytical and theoretical works, as well as in the development of public development programs, they give a rather serious failure and significant distortion of the final output data in individual subject-specific cases. Nevertheless, this does not diminish or implore their importance and significance, especially in helping researchers in the Humanities and Natural Sciences. In this paper, we will consider the problems of creating digital models for predicting the Muslim population growth. We will study Northern Europe as an example, identify the critical vulnerabilities of these models, and analyze the causes of their failure methodologically. The authors will present the actual variance in the original sources of statistics, indicate and justify the failure of some local conventional concepts and actual irrelevance of national systems of open metadata database, which in fact are the source of confusion for both ordinary researchers and corporations.