 Hard science and soft science are colloquial terms used to compare scientific fields on the basis of perceived methodological rigor, exactitude, and objectivity. Roughly speaking natural sciences e.g. biology, chemistry, physics are considered hard whereas the social sciences e.g. economics, psychology, sociology are usually described as soft. Precise definitions vary, but features often cited as characteristic of hard science include producing testable predictions, performing controlled experiments, relying on quantifiable data and mathematical models, a high degree of accuracy and objectivity, higher levels of consensus, faster progression of the field, greater explanatory success, accumulatedness, replicability, and generally applying a purer form of the scientific method. A closely related idea originating in the 19th century with Augusta Cohn is that scientific disciplines can be arranged into a hierarchy of hard to soft on the basis of factors such as rigor, development and whether they are basic or applied. Some philosophers and sociologists of science have questioned the relationship between these characteristics and perceived hardness or softness. The more developed hard sciences do not necessarily have a greater degree of consensus or selectivity in accepting new results. Commonly cited methodological differences are also not a reliable indicator. For example, social sciences such as psychology and economics use mathematical models extensively, but are usually considered soft sciences. However, there are some measurable differences between hard and soft sciences. For example, hard sciences make more extensive use of graphs, and soft sciences are more prone to a rapid turnover of buzzwords. The metaphor has been criticized for unduly stigmatizing soft sciences, creating an imbalance in the public perception, funding, and recognition of different fields.