Where does gap collide?

The range of energies that an electron in a solid is forbidden to occupy, lying between the highest filled band of states and the lowest empty one: its width sets whether a material conducts, insulates, or behaves as a semiconductor. Wilson's 1931 The theory of electronic semi-conductors explained conduction in these materials in terms of electrons that must be lifted across this forbidden interval, giving the modern account of the energy gap. The referent is a property of the allowed energy levels of a crystal, measured in electron-volts, and it has nothing to do with a wage difference between groups, a shortfall in service quality, or a channel joining two cells.[1]

Unit

The width of the forbidden energy interval, in electron-volts

Recovery means

Not applicable

Measured by

Determined from optical absorption edges, electrical conductivity versus temperature, or photoemission spectroscopy

The measured difference in average earnings between two groups of workers, most often expressed as the ratio of women's pay to men's pay across a labour market. Blau and Kahn's 2017 The Gender Wage Gap: Extent, Trends, and Explanations reviewed how large this difference is, how much of it human capital and occupation explain, and how much remains unaccounted for. The referent is a statistical disparity in observed wages across a population, reported as a percentage or ratio, and it is unrelated to a forbidden energy interval in a crystal, a shortfall between promised and delivered service, or a junction between adjacent cells.[2]

Unit

A group earnings difference, as a ratio or percentage of pay

Recovery means

Not applicable

Measured by

Estimated from wage surveys and decomposed into explained and unexplained parts by regression methods

The shortfall between what a customer expects from a service and what the customer perceives they received, treated as the quantity a firm must close to raise quality. Parasuraman, Zeithaml, and Berry's 1985 A Conceptual Model of Service Quality set out a gaps model in which this expectation-perception difference results from four internal gaps in how a firm understands, specifies, delivers, and communicates its service. The referent is a perceived difference between expected and delivered service, assessed by customer ratings, and it shares nothing with an energy interval in a solid, a wage disparity across groups, or a cellular channel beyond the word.[3]

Unit

The expectation-minus-perception difference on a service-quality scale

Recovery means

Closing the gap by aligning delivery and communication with customer expectations

Measured by

Scored by survey instruments such as SERVQUAL that rate expectations against perceptions across service dimensions

A cluster of channels that directly connects the interiors of two neighbouring cells, letting ions and small molecules pass from one cytoplasm to the other without entering the space between them. Goodenough and Paul's 2009 Gap Junctions reviewed how these channels are built from connexin proteins and how they coordinate electrical and chemical signalling between cells. The referent is a physical structure spanning the narrow space between two cell membranes, counted as channels per junction, and it bears no relation to a forbidden energy band, an earnings disparity, or a shortfall in perceived service quality.[4]

Unit

A cell-to-cell channel cluster, by number of connexin channels

Recovery means

Not applicable

Measured by

Imaged by electron microscopy and probed by dye transfer or electrical coupling between paired cells

In literary theory, gap refers to the blanks or gaps that a text leaves unsaid, which readers fill in and so take part in producing its meaning. This meaning comes from Iser (1980) in The Act of Reading.[5]

Unit

Recovery means

Measured by