A measure, H, of variability. Denoting the frequency of the jth distinct value in a sample of size N by nj,
Often used in the context of market shares, when it is usually multiplied by 10 000.
A measure of firm size relative to market size used as an indicator of market power. The Herfindahl index is defined as the sum of the squares of market shares of the firms operating in a market, H = Σisi2, where si is the market share of the ith firm. If there are N firms, the lowest value H can take is when all N firms have equal shares, so that si = 1/N for all i, and H = 1/N. The highest value H can take is 1, which is approached as the market share of the largest firm tends to 1 and the market shares of the rest tend to 0. H thus rises as concentration increases. The advantage of the Herfindahl index over the N-firm concentration ratio is that it is sensitive to the distribution of market share among firms. See also Lerner index.
- heat shield
- heat-shock protein
- heat sink
- heat transfer
- heat transfer coefficient
- heat treatment
- heave
- heaven
- heavily indebted poor countries
- Heaviside function
- Heaviside layer
- Heaviside, Oliver
- Heaviside–Kennelly layer
- Heaviside–Lorentz units
- heavy chemicals
- heavy client
- heavy element
- heavy-fermion system
- heavy hydrogen
- heavy-ion counter
- heavy key
- heavy liquids
- heavy-medium separation
- heavy metal
- heavy-metal pollution