the Chicago school developed symbolic interactionism. Meanwhile, in the 1930s, the Frankfurt School pioneered the idea of critical theory, an interdisciplinary form of Marxist sociology drawing upon thinkers as diverse as Sigmund Freud and Friedrich Nietzsche. Critical theory would take on something of a life of its own after World War II, influencing literary criticism and the Birmingham School establishment of cultural studies. Sociology evolved as an academic response to the challenges of modernity, such as industrialization, urbanization, secularization, and a perceived process of enveloping rationalization. The field generally concerns the social rules and processes that bind and separate people not only as individuals, but as members of associations, groups, communities and institutions, and includes the examination of the organization and development of human social life. The sociological field of interest ranges from the analysis of short contacts between anonymous individuals on the street to the study of global social processes. In the terms of sociologists Peter L. Berger and Thomas Luckmann, social scientists seek an understanding of the Social Construction of Reality. Most sociologists work in one or more subfields. One useful way to describe the discipline is as a cluster of sub-fields that examine different dimensions of society. For example, social stratification studies inequality and class structure; demography studies changes in population size or type; criminology examines criminal behaviour and deviance; and political sociology studies the interaction between society and state. Since its inception, sociological epistemologies, methods, and frames of enquiry, have significantly expanded and diverged. Sociologists use a diversity of research methods, collecting both quantitative and qualitative data, draw upon empirical techniques, and engage critical theory. Common modern methods include case studies, historical research, interviewing, participant observation, social network analysis, survey research, statistical analysis, and model building, among other approaches. Since the late 1970s, many sociologists have tried to make the discipline useful for purposes beyond the academy. The results of sociological research aid educators, lawmakers, administrators, developers, and others interested in resolving social problems and formulating public policy, through subdisciplinary areas such as evaluation research, methodological assessment, and public sociology. In the early 1970s, women sociologists began to question sociological paradigms and the invisibility of women in sociological studies, analysis, and courses. In 1969, feminist sociologists challenged the discipline's androcentrism at the American Sociological Association's annual conference. This led to the founding of the organization Sociologists for Women in Society, and, eventually, a new sociology journal,