Diversity is the presence of a wide range of variation in the qualities or attributes under discussion.
Amongst humans, particularly in a social context, the term diversity refers to the presence in one population of a wide variety of cultures, opinions, ethnic groups, socio-economic backgrounds, and so on. See also human variability.
At the international level, diversity refers to the existence of many peoples contributing their unique experiences to humanity's culture. The preservation of our planet's formidable linguistic and cultural diversity in the context of world wide economic integration is the object of great concern to many people in the wake of the 21st century.
It is often used in conjunction with the term tolerance in political creeds which support the idea that such diversity is valuable and desirable.
Critics of diversity claim that in the political arena, diversity is a code word for forcing people to tolerate or approve people and practices they find repugnant. Critics also point out that diversity programs in education and business inherently emphasize minority groups (e.g. African-Americans, Latinos, and women) and do not give equal time to non-minority groups (white males). They claim that pluralism is a more accurate term for the presence of variation, and that, under the banner of "diversity," groups actually forbid criticism of protected groups by restricting what they call hate speech.
"Diversity" or the phrase "to respect (someone's) diversity" has also been used to refer to sexual orientation and appears in the name of Montréal's annual gay pride celebration, DiversCité.
"Respect for Diversity" is one of the six principles of the Global Greens Charter, a manifesto of Green parties from all over the world subscribed to.
In this political context, the word diversity is somewhat meaningless or differently understood outside of North America: for example in the UK the US concept of diversity does not wholly exist as there is no UK context for US affirmative action programs. This is not to say that others are not supportive of the underlying agenda of US diversity, but it is described with different words, such as using "respect", "tolerance" and "multi-cultural" as the context requires.
Diversity describes the structure of ecological communities. This does not only involve the number of species, but also the number of individuals of each species. Several Diversity indices have been established, amongst which the Shannon-Weaver Diversity Index is frequently used. See also biodiversity.
Radio and telecommunications
"Diversity reception" refers to a technique of monitoring multiple frequencies from the same signal source, or multiple radios and antennas monitoring the same frequency, in order to combat signal fade and interference. This approach selects the signal from one receiver whenever another loses the signal.
In a business context, diversity is approached as a strategy for improving employee retention and increasing consumer confidence. The "business case for diversity", as it is often phrased, is that in a global and diverse marketplace, a company whose makeup mirrors the makeup of the marketplace it serves is better equipped to thrive in that marketplace than a company whose makeup is homogenous. Business diversity consultants and diversity trainers often treat the social consequences of diversity as secondary; their primary focus is to enable the company to function in a heterogeneous or global economy. Companies with diversity programs are usually national or international in scope, or are composed of large groups of workers who come from differing backgrounds. Having both Wikipedia and Wikinfo can be seen as similar to this kind of diversity.
Variation between individuals in the population. Typically diversity refers to genetic variation. In bit string genetic algorithms, diversity may be measured by Hamming distance (i.e. counting the number of bits that are different) between bit strings. [Koza, 1992] defines variety in the population by the number of unique programs it contains, but this measure takes no notice of the fact that the behaviour of genetically different programs can be very similar or even identical. [Foundations of Genetic Programming].
Recently research papers have suggested more sophisticated ways of measuring diversity.