 Modern philosophical discussions about measurement—spanning from the late nineteenth century to the present day—may be divided into several strands of scholarship. These strands reflect different perspectives on the nature of measurement and the conditions that make measurement possible and reliable. The main strands are mathematical theories of measurement, operationalism, conventionalism, realism, information-theoretic accounts and model-based accounts. These strands of scholarship do not, for the most part, constitute directly competing views. Instead, they are best understood as highlighting different and complementary aspects of measurement. The following is a very rough overview of these perspectives: