Where does stratification collide?

The arrangement of a society into a ranked hierarchy of layers, or strata, so that people in higher layers hold more wealth, status, and power than those below, and position tends to be passed on and defended. Davis and Moore's 1945 Some Principles of Stratification argued that societies rank their positions by how important and hard to fill they are, a functional claim that later scholars sharply disputed. The referent is a durable order of human inequality, mapped by class, occupation, and mobility, and it has nothing to do with layers of rock, layers of water, or the deliberate splitting of a sample.[1]

Unit

A ranked social layer, defined by shared wealth, status, and power

Recovery means

Not applicable

Measured by

Indexed by occupation, income, education, and studies of movement between layers across generations

The layering of sediment into distinct beds and laminae as it settles and hardens over time, so that a cliff face reads as a stack of strata, with older layers below younger ones unless the rock has been overturned. Campbell's 1967 Lamina, Laminaset, Bed and Bedset defined the hierarchy of physical layers, the bounding surfaces that separate them, and how each records a distinct spell of deposition. The referent is a record of time written in stacked rock, dated by superposition, and it is unrelated to the ranking of a society, the warming of a lake, or a step in drawing a sample.[2]

Unit

A single bed or lamina of sediment, bounded by depositional surfaces

Recovery means

Not applicable

Measured by

Logged by measuring bed thickness, grain size, and bounding surfaces in outcrop and drill core

The separation of a body of water into stable layers of different temperature and density, so that a warm, light surface layer floats on a cold, dense deep layer with a sharp transition, the thermocline, between them. Boehrer and Schultze's 2008 review Stratification of Lakes set out how heating, wind, and salinity build and break these layers, and how seasonal mixing, or turnover, overturns them. The referent is a density structure in a fluid that resists vertical mixing, gauged by depth profiles, and it shares nothing with social rank, stacked rock, or a sampling design beyond the word.[3]

Unit

A layer of water of near-uniform temperature and density, by depth

Recovery means

Seasonal cooling and wind erode the layering, and turnover mixes the water column top to bottom

Measured by

Profiled with temperature and density sensors lowered through the water column to locate the thermocline

The deliberate division of a population into internally similar subgroups, or strata, before sampling, so that each subgroup is sampled on its own and the parts combine into a more precise estimate for the whole. Neyman's 1934 paper On the Two Different Aspects of the Representative Method placed stratified sampling on a firm footing and showed how allocating the sample across strata sharpens an estimate. The referent is a procedure chosen by the analyst to control variance, defined by how a population is partitioned, not a layer of society, a bed of rock, or a zone of a lake.[4]

Unit

A subgroup of the population sampled as its own unit

Recovery means

Not applicable

Measured by

Realised by partitioning the frame on known variables and drawing a sample within each stratum

In archaeology, stratification refers to the study of the order of deposition of layers and interfaces on a site, recorded as a sequence. This meaning comes from Harris (1989) in Principles of Archaeological Stratigraphy.[5]

Unit

Recovery means

Measured by