Higher education includes both the teaching and the research activities of universities, and within the realm of teaching, it includes both the undergraduate level (sometimes referred to as tertiary education) and the postgraduate level (sometimes referred to as quaternary education). Higher education differs from other forms of third-level education such as vocational education. However most professional education is included within higher education, and many postgraduate qualifications are strongly vocationally oriented, for example in disciplines such as law and medicine.
In most developed countries a high proportion of the population (up to 50%) now enter higher education at some time in their lives. Higher education is therefore very important to national economies, both as a significant industry in its own right, and as a source of trained and educated personnel for the rest of the economy; it is often argued that in a modern economy the quantity and quality of such human capital is the most important factor underlying economic growth.