OADEM 2021 is a project where we analyse big data generated from Census programmes conducted by the Office for National Statistics. We are currently developing methods for the automated detection of outliers and anomalies which may be generated in census programmes. This research project enables the understanding of the presence of outliers and anomalies in the big data stacks using machine learning techniques as well as traditional statistical methods. The data is semi-structured as we are moving from traditional census methods to online methods. This work is in collaboration with the Office for National statistics and colleagues from S3RI of the University of Southampton