Volume 25 Number 3 September 2001
260 APPLIED PSYCHOLOGICAL MEASUREMENT
several cognitive components are required simultaneously for successful task performance. For the
MLTM, successful performance on an item/task involves the conjunction of successful performances
on several subtasks, each of which follows a separate unidimensional
IRT model (e.g., the Rasch
model),
P
X
j
= 1|θ
i
=
K
k=1
P
X
jk
= 1|θ
ik
=
K
k=1
exp(θ
ik
− β
jk
)
1 + exp(θ
ik
− β
jk
)
. (4)
Generally, conjunctive approaches have been preferred in cognitive assessment models that
focus on a single strategy for performing tasks (Corbett, Anderson, & O’Brien, 1995; Tatsuoka,
1995; VanLehn & Niu, in press; VanLehn, Niu, Siler, & Gertner, 1998). Multiple strategies are
often accommodated with a hierarchical latent-class structure that divides examinees into latent
classes according to strategy. A different model is used within each class to describe the influence of
attributes on task performance (e.g., Mislevy, 1996; Rijkes, 1996). Within a single strategy, models
involving more-complicated combinations of attributes driving task performance are possible (e.g.,
Heckerman, 1998), but they can be more challenging to estimate and interpret. The present paper
focuses on two discrete latent space analogues of the
MLTM that make few assumptions about
the relationship between latent attributes and task performance beyond a stochastic conjunctive
structure.
Assessing Transitive Reasoning in Children
Method
Sijtsma & Verweij (1999) analyzed data from a set of transitive reasoning tasks. The data
consisted of the responses to nine transitive reasoning tasks from 417 students in second, third, and
fourth grade. Examinees were shown objects A, B, C,
... , with physical attributes Y
A
,Y
B
,Y
C
,
.... Relationships between attributes of all pairs of adjacent objects in an ordered series, such as
Y
A
<Y
B
and Y
B
<Y
C
, were shown to each examinee. The examinee was asked to reason about the
relationship between some pair not shown, for example,
Y
A
and Y
C
. Reasoning that Y
A
<Y
C
from
the premises
Y
A
<Y
B
and Y
B
<Y
C
, without guessing or using other information, is an example of
transitive reasoning (for relevant developmental psychology, see Sijtsma & Verweij, 1999; Verweij,
Sijtsma, & Koops, 1999).
The tasks were generated by considering three types of objects (wooden sticks, wooden disks,
and clay balls) with different physical attributes (sticks differed in length by .2 cm per pair, disks
differed in diameter by .2 cm per pair, and balls differed in weight by 30 g per pair). Each task
involved three, four, or five of the same type of object.
For a three-object task, there were two premises, AB (specifying the relationship between
Y
A
and Y
B
) and BC (similarly for Y
B
and Y
C
). There was one item, AC, which asked for the relationship
between
Y
A
and Y
C
. For a four-object task, there were three premises (AB, BC, and CD) and two
items (AC and BD). For a five-object task, there were four premises (AB, BC, CD, DE) and three
items (AC, BD, and CE). Tasks, premises, and items within tasks were presented to each examinee
in random order. Explanations for each answer were recorded to evaluate the use of strategy.
Table 1 summarizes the nine tasks.
Results
Sijtsma & Verweij (1999) showed that the task response data fit a polytomous monotone homo-
geneity model (a model assuming only
LI, unidimensionality, and monotonicity; see Van der Ark,
2001) well when (1) each item within a task was scored as correct
—when a correct response and a
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