Related Experiment Video
Updated: Aug 15, 2026

Experimental Protocol for Manipulating Plant-induced Soil Heterogeneity
Published on: March 13, 2014
Sequential assignment and treatment-as-usual. Alternatives to standard experimental designs in field studies of
Abstract:
Psychosocial treatment research studies encounter obstacles to random assignment (RA). Used together, two procedures offer an alternative to the standard RA design. First, sequential assignment (SA) may create less opposition from administration, staff, and clients. SA operates on the principle that limited bed availability, a common treatment consideration in the field, determines assignment of clients to conditions. Second, treatment-as-usual (TAU) represents an alternative type of control condition. Some clients on the waiting list will, before a slot opens up and they enter an experimental condition, be absorbed into the existing treatment system, in which the amount and type of treatment they receive can vary widely. Substituting SA and TAU for the standard RA design may introduce methodological impurities including certain limited biases.
Related Concept Videos
Group Design
Data Collection by Experiments
An example of the experimental method is a public clinical trial...
Experimental Designs
Crossover Experiments
Crossover designs are performed even with smaller sample sizes since the samples can act as their controls. These are better than simple randomized trials since patients are exposed to all the treatments.
Bioequivalence Experimental Study Designs: Completely Randomized and Randomized Block Designs
Bioequivalence Experimental Study Designs: Repeated Measures, Cross-Over, Carry-Over, and Latin Square Designs

