In strict definition, an experimentally observable effect (on rates of reaction, etc.) of the @[email protected] of charge through a chain of atoms by electrostatic induction. A theoretical distinction may be made between the @[email protected], and the inductive effect as models for the @[email protected] interaction between a given site within a @[email protected] and a remote unipole or dipole within the same entity. The experimental distinction between the two effects has proved difficult, except for molecules of peculiar geometry, which may exhibit 'reversed field effects'. Ordinarily the inductive effect and the @[email protected] are influenced in the same direction by structural changes in the molecule and the distinction between them is not clear. This situation has led many authors to include the @[email protected] in the term 'inductive effect'. Thus the separation of values into inductive and @[email protected] components does not imply the exclusive operation of a through-bonds route for the @[email protected] of the non-conjugative part of the substituent effect. To indicate the all-inclusive use of the term inductive, the phrase 'so-called inductive effect' is sometimes used. Certain modern theoretical approaches suggest that the 'so-called inductive effect' reflects a @[email protected] rather than through-bonds @[email protected]