Table 2 Experimental design
Criteria | Category | Number of studies | % |
|---|---|---|---|
Type of design | Full factorial | 1 | 2.9% |
Fractional factorial | 19 | 55.9% | |
“Efficient design” | 6 | 17.6% | |
Bayesian efficient design | 5 | 14.7% | |
Not reported | 3 | 8.8% | |
Generation of choice sets | Software | 22 | 64.7% |
Manual | 2 | 5.9% | |
Not reported | 9 | 26.5% | |
Design aims | Level balance | 7 | 14.7% |
Minimal overlap | 3 | 8.8% | |
Orthogonality | 14 | 41.2% | |
Other | 1 | 2.9% | |
Design efficiency | D-Efficient | 16 | 47.1% |
Unclear or not reported | 18 | 52.9% | |
Blocked design | Blocked | 27 | 79.4% |
No blocking | 3 | 8.8% | |
Unclear or not reported | 4 | 11.8% |