Comparing the results of one‐session, two‐session, and three‐session <scp>MSWO</scp> preference assessments
Two-session MSWO gives a close hierarchy, but run three sessions when the top item must be right.
01Research in Context
What this study did
Conine et al. (2021) asked if you can run fewer MSWO sessions and still trust the results.
They compared one-session, two-session, and three-session MSWOs with the same group.
The goal was to see if shorter tests keep the same item rankings and top pick.
What they found
The shorter tests made lists that looked a lot like the full three-session list.
But the very top item often changed when they cut to one or two sessions.
If you need to be sure of the single best reinforcer, run all three sessions.
How this fits with other research
Hastings et al. (2001) already showed a 30-second single-item test can predict reinforcer strength.
Their ultra-brief method worked, yet Conine shows that even two MSWO sessions may miss the true top item.
The difference is simple: P used engagement time, while Conine used choice ranks.
Ford et al. (2022) later used MSWO with adults who have neurocognitive disorder.
They found single-stimulus tests worked better than rank-order for that group.
Together, the papers say: shortening is possible, but pick the shortcut that matches your goal and population.
Why it matters
You can save time by running only two MSWO sessions when you just need a rough hierarchy.
Reserve the full three sessions for cases where the single best reinforcer is critical, such as intensive DTT or crisis intervention.
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02At a glance
03Original abstract
The multiple-stimulus-without-replacement (MSWO) preference assessment is commonly used in behavior-analytic research and practice. As originally published, the MSWO included 5 sessions in an effort to confirm stimulus preferences. Subsequent researchers have evaluated the validity of MSWO outcomes when the assessment is abbreviated. Generally, valid outcomes have been noted for 3-session MSWOs (that is, the outcomes match those of the 5-session version), while validity outcomes for 1- or 2-session MSWOs have varied across studies. The current study utilized data from 157 MSWO preference assessments conducted in previously published research with 49 total participants and analyzed the extent to which 1-session or 2-session variations of those assessments would have yielded similar outcomes as a 3-session assessment. Results indicate that the hierarchies produced by both abbreviated formats were strongly correlated with those produced by a 3-session assessment. However, neither 1- nor 2-session MSWOs reliably identified the same highest-preferred stimuli as a 3-session MSWO.
Journal of Applied Behavior Analysis, 2021 · doi:10.1002/jaba.808