The influence of distractor strength and response order on MCQ responding

Multiple-choice questions (MCQs) play a key role in standardised testing and in-class assessment. Research into the influence of within-item response order on MCQ characteristics has been mixed. While some researchers have shown preferential selection of response options presented earlier in the answer list, others have failed to replicate these results. This paper investigates a possible explanation for these mixed findings by assessing the influence of distractor strength on MCQ response order effects. A real-world assessment was administered to 232 undergraduates in which the response order within items was systematically varied. A generalised multilevel model was then used to show a significant interaction between distractor strength and response position with regard to response behaviour. Furthermore, the effect was found to be independent of student ability. These findings have implications for MCQ test construction, minimising the negative consequences of MCQ test exposure and promoting improved test-taking strategies.     

Velocity observer design for the consensus in delayed robot networks

The consensus problem for networks of multiple agents consists in reaching an agreement between certain coordinates of interest using a distributed controller. It may be desirable that all the agents find a consensus at a given desired leader coordinate (Leader Follower Consensus Problem LFCP), or it may be only necessary that they agree at a certain coordinates value (Leaderless Consensus Problem LCP). Consensus has many practical applications in robot networks systems, where the interconnection of the agents may present variable time delays, hence rendering the stability analysis and control design more complex. Another problem that may arise is the possible lack of velocity measurements. In this work, a Proportional plus damping injection (P + d) controller together with a linear velocity observer is introduced. Our approach is able to solve both the LFCP and the LCP in networks of robots modeled as undirected weighted graphs with unknown asymmetric (bounded) variable time delays. Local (semi global) asymptotic stability is proven and simulation results are provided to test the performance of the proposed scheme.