Michael Schiffer defined two ways in which formation processes can distort or transform the archaeological record: namely by N-transforms (natural) or C-transforms (cultural). N-transforms include processes such as the weathering of exposed objects, or soil disturbance by animals whilst C-transforms include activity by people such as the recycling of objects, 'robbing' of structures for re-usable building materials. Schiffer's ideas came about as a reaction against the oversimplifying theory of 'entropy'—in which the quantity and quality of artefacts in the archaeological record are diminished over time. Schiffer has pointed out that this view doesn't take into account the specificity of individual cases (and the multitude of variables such as the nature of soil disturbances, the materials being discussed etc.) and the idea that important information can be added to the archaeological record over time (e.g. 'ecofacts' - environmental data).

Experimental archaeologists have conducted trials to investiage the specific processes at work in archaeological formation. For instance, the Overton Down project involves the burial of artefacts made from different materials (e.g. bone, glass, pot, flint, wood, metals) in a bank and ditch especially constructed for the project. Archaeologists then excavated these objects after 2, 4, 8, 16, 32, 64, and 128 years in the soil. The project began in the 1960s and the last excavation is scheduled for 2088.

"From the artifact's standpoint the environment is filled with hostile forces. Chemical, biological, and physical agents singly and in combination reduce artifacts to simpler and more stable forms" (Schiffer, 145). Schiffer discusses not only the different chemical, physical and biological agents that can affect different materials, but he also looks at different disturbance processes such as trampling, ploughing and burrowing.

This is all very well for an set of beads buried in a pit, but buildings and cities present a much more complex set of processes. Within a building there is a whole host of different construction materials and artefacts. The archetypal archaeological site is perhaps the Roman town of Pompeii, but this - buried by volcanic ash and rock - is a very different kind of site from the settlement which has gradually fallen into ruin.