Continuity/discontinuity issue refers to a debate among theorists about whether developmental changes are quantitative and continuous, or qualitative and discontinuous, that is, stage
like; or about whether developmental changes are best characterized as gradual and quantitative or, rather, abrupt and qualitative; or whether a particular developmental phenomenon represents a smooth progression throughout the life span (continuity) or a series of abrupt shifts (discontinuity)
(See also Continuity versus discontinuity of development or continuity-discontinuity controversy)