[...] [T]he application of discrete choice experiments (DCEs) in health economics has seen an increase over the last few years. While the number of studies using DCEs is growing, there has been relatively limited consideration of experimental design theory and methods. Details of the development of the designed experiment are rarely discussed. Many studies have used small fractional factorial designs (FFDs), generated with commercial design software packages, e.g. orthogonal main effects plans (OMEPs), sometimes manipulated in ad hoc ways (e.g. randomly pairing up scenarios or taking one scenario from the design and combining it with every other scenario). Such approaches can result in designs with unknown statistical design properties, in particular with unknown correlations between parameter estimates.