ABSTRACT
With the rise in attention to randomized controlled trials (RCTs) in educational research, experimentation has considerable prominence, particularly in its claim to address causality. This chapter sets out features of, advantages and disadvantages, claims and counter-claims in RCTs and its variants, and other kinds of experimental designs, and identifies a range of different types of experiment and quality criteria in experimentation (e.g. how we know if an experiment has ‘worked’ and that the results are valid and reliable). It identifies the characteristics of, and requirements for, a ‘true’ experiment, with special attention to randomization, controls and controlled interventions, and distinguishes ‘true’ RCTs from field experiments, natural experiments, quasi-experiments, single-case experiments and retrospective (ex post facto) experiments. The chapter provides advice on how to select an experimental design; how to plan, conduct and report experiments; and how to address threats to validity and reliability. The chapter also addresses issues in design experiments and Internet-based experiments.
