At the current stage of its development, the economy is increasingly referred to as digital, but everyone interprets this term in his or her own way. Therefore, first of all the authors disproved the existing hypothesis of the «universal incomprehension of the digital economy». The authors analyzed different approaches of Russian scientists to this issue and concluded that the views of Russian scientists and specialists do not differ much from the approaches of their foreign colleagues. Based on the understanding of digital economy essence, the authors differentiated digital and digitalized economy, applying the concept of intensive and extensive use of information and communication technologies (ICT). Having defined the essence of these definitions, the authors raised the question of the methodologies for measuring the digital economy, as well as the possibilities and attempts to measure certain types of activities in a digitalized economy. The article provides a brief description and methodology for calculating the currently existing indices for assessing the development of the digital economy: the ICT development index; Huawei Global Networking Index; e-government development index; the digital economy and society index and the international digital economy and society index; the digitalization index of the economy of the Boston Consulting Group; global digital competitiveness index; digital evolution index; Ivanov digital index. The article shows the ranks of the Russian Federation according to these indices. After analyzing and comparing the methodology for calculating the indices, the authors concluded that all indices are global, i.e. they assess the country's position as a whole in terms of the development of the digital economy. The authors concluded that the global calculating methodology of indices does not show the country's rating in relation of its participation in breakthrough technologies research. Additionally, according to the authors, there are no indicators that could measure the digitalization level of individual industries and services. Thus, the authors identified further areas of their research.