EDUCATIONAL PSYCHOLOGIST, 42(2), 99–107
2007, Lawrence Erlbaum Associates, Inc.
Scaffolding and Achievement in Problem-Based and Inquiry Learning:
A Response to Kirschner, Sweller, and Clark (2006)
Cindy E. Hmelo-Silver, Ravit Golan Duncan, and Clark A. Chinn
Department of Educational Psychology
Many innovative approaches to education such as problem-based learning (PBL) and inquiry
learning (IL) situate learning in problem-solving or investigations of complex phenomena.
Kirschner, Sweller, and Clark (2006) grouped these approaches together with unguided discov-
ery learning. However, the problem with their line of argument is that IL and PBL approaches
are highly scaffolded. In this article, we ﬁrst demonstrate that Kirschner et al. have mistakenly
conﬂated PBL and IL with discovery learning. We then present evidence demonstrating that
PBL and IL are powerful and effective models of learning. Far from being contrary to many
of the principles of guided learning that Kirschner et al. discussed, both PBL and IL employ
scaffolding extensively thereby reducing the cognitive load and allowing students to learn in
complex domains. Moreover, these approaches to learning address important goals of educa-
tion that include content knowledge, epistemic practices, and soft skills such as collaboration
and self-directed learning.
WHY PROBLEM-BASED AND INQUIRY
LEARNING ARE NOT MINIMALLY GUIDED:
ON ASSUMPTIONS AND EVIDENCE
All learning involves knowledge construction in one form or
another; it is therefore a constructivist process. The question
of what sorts of instructional practices are likely to promote
such knowledge construction, or learning, is at the core of the
argument presented by Kirschner, Sweller, and Clark (2006).
The authors loosely deﬁne minimally guided instruction as
a learning context in which “learners, rather than being pre-
sented with essential information, must discover or construct
essential information for themselves” (p. 1). They conversely
deﬁne direct guidance instruction as “providing information
that fully explains the concepts and procedures that students
are required to learn.” In their argument, Kirschner et al.
contrast minimally guided instructional approaches with ap-
proaches that provide direct instructional guidance and assert
that minimally guided instructional approaches are ineffec-
tive and inefﬁcient.
Correspondence should be addressed to Cindy E. Hmelo-Silver, Depart-
ment of Educational Psychology, Rutgers University, 10 Seminary Place,
New Brunswick, NJ 08901-1183. E-mail: email@example.com
There are two major ﬂaws with Kirschner et al’s argument.
The ﬁrst is a pedagogical one. Kirschner and colleagues have
indiscriminately lumped together several distinct pedagog-
ical approaches—constructivist, discovery, problem-based,
experiential, and inquiry-based—under the category of min-
imally guided instruction. We argue here that at least some
of these approaches, in particular, problem-based learning
(PBL) and inquiry learning (IL), are not minimally guided
instructional approaches but rather provide extensive scaf-
folding and guidance to facilitate student learning.
The second is a ﬂaw in their evidentiary base. The claim
by Kirschner et al. that approaches such as PBL and IL
are ineffective is contrary to empirical evidence that indeed
does support the efﬁcacy of PBL and IL as instructional
approaches. This evidence suggests that these approaches
can foster deep and meaningful learning as well as signiﬁcant
gains in student achievement on standardized tests.
In our article we will discuss how PBL and IL provide
instructional guidance and provide evidence that supports
the efﬁcacy of these pedagogical approaches. We will exam-
ine the claims of Kirschner et al. speciﬁcally in the context
of PBL and IL, as these approaches clearly provide scaf-
folding for student learning. We begin with a brief discus-
sion of the qualities of some of the pedagogical approaches
100 HMELO-SILVER, DUNCAN, CHINN
Kirschner et al. have included under their “minimally guided”
ARE PBL AND IL INSTANCES OF MINIMALLY
Constructivist theories of learning stress the importance of
learners being engaged in constructing their own knowledge
(Mayer, 2004; Palincsar, 1998). An assumption that leads to
the minimally guided discovery approach is that the learn-
ers need to explore phenomena and/or problems without any
guidance. This assumption has been repeatedly demonstrated
to be ﬂawed (Mayer, 2004). We agree with Kirschner et al.
(2006) that there is little evidence to suggest that unguided
and experientially-based approaches foster learning. How-
ever, IL and PBL are not discovery approaches and are not
instances of minimally guided instruction, contrary to the
claims of Kirschner et al. Rather, PBL and IL provide con-
siderable guidance to students.
Before we discuss the ways in which PBL and IL are not
minimally guided, we begin by clarifying what is meant by
PBL and IL. In PBL, students learn content, strategies, and
self-directed learning skills through collaboratively solving
problems, reﬂecting on their experiences, and engaging in
self-directed inquiry. In IL, students learn content as well
as discipline-speciﬁc reasoning skills and practices (often in
scientiﬁc disciplines) by collaboratively engaging in investi-
gations. Both PBL and IL are organized around relevant, au-
thentic problems or questions. Both place heavy emphasis on
collaborative learning and activity. In both, students are cog-
nitively engaged in sense making, developing evidence-based
explanations, and communicating their ideas. The teacher
plays a key role in facilitating the learning process and may
provide content knowledge on a just-in-time basis.
The major distinction that we perceive between PBL and
IL is their origins. PBL has its origins in medical education
and is based on research on medical expertise that empha-
sized a hypothetical-deductive reasoning process (Barrows
& Tamblyn, 1980). PBL often uses text-based resources for
both the problem data and self-directed learning. IL has its
origins in the practices of scientiﬁc inquiry and places a heavy
emphasis on posing questions, gathering and analyzing data,
and constructing evidence-based arguments (Kuhn, Black,
Keselman, & Kaplan, 2000; Krajcik & Blumenfeld, 2006).
As we have examined the broad variety of instantiations of
PBL and IL, we have not uncovered any dimensions that con-
sistently distinguish between PBL and IL. Indeed, we think
there are no clear-cut distinguishing features. PBL frequently
engages students in explorations and analyses of data, such
as one would expect IL environments to do, and IL frequently
poses problems and asks students to consult various resources
to solve them as PBL environments do. For example, prob-
lems in medical PBL present students with rich sets of pa-
tient data to analyze (Barrows, 2000; Hmelo-Silver, 2004).
Similarly, IL environments such as the Web Integrated Sci-
ence Environment (WISE) provide students with scientiﬁc
problems and the research materials that students examine
in order to reach a conclusion about the problem (Linn &
Slotta, 2006). Students may read a variety of resources in ad-
dition to reading about data and conducting their own studies.
Thus, in practice PBL and IL environments are often indis-
tinguishable, despite divergent origins and so we treat them
as synonymous in this article.
As we have noted, PBL and IL environments are not mini-
mally guided because of many forms of scaffolding provided.
Moreover, these approaches may include direct instruction
as one of the strategies they employ (Krajcik, Czerniak, &
Berger, 1999; Schmidt, 1983; Schwartz & Bransford, 1998).
However, in these contexts, direct instruction may be pro-
vided on a just-in-time basis and generally once students ex-
perience a need to know the information presented (Edelson,
2001). Thus a mini-lecture or benchmark lesson presenting
key information to students is used when students understand
the necessity of that information and its relevance to their
problem-solving and investigational practices. Such just-in-
time direct instruction promotes knowledge construction in a
way that makes knowledge available for future use in relevant
contexts (Edelson, 2001).
There is an extensive body of research on scaffold-
ing learning in inquiry- and problem based environments
(Collins, Brown, & Newman, 1989; Davis & Linn, 2000;
Golan, Kyza, Reiser, & Edelson, 2002; Guzdial, 1994; Jack-
son, Stratford, Krajcik, & Soloway, 1994; Reiser, 2004; Toth,
Suthers, & Lesgold, 2002), and researchers have developed
theory-driven and empirically based design guidelines for in-
corporating effective scaffolding strategies to support learn-
ing (Hmelo & Guzdial, 1996; Hmelo-Silver, 2006; Quintana
et al., 2004; Reiser et al., 2001).
Scaffolded inquiry and problem-based environments
present learners with opportunities to engage in complex
tasks that would otherwise be beyond their current abilities.
Scaffolding makes the learning more tractable for students
by changing complex and difﬁcult tasks in ways that make
these tasks accessible, manageable, and within student’s zone
of proximal development (Rogoff, 1990; Vygotsky, 1978).
Quintana et al. (2004) conceived of scaffolding as a key ele-
ment of cognitive apprenticeship, whereby students become
increasingly accomplished problem-solvers given structure
and guidance from mentors who scaffold students through
coaching, task structuring, and hints, without explicitly giv-
ing students the ﬁnal answers. An important feature of scaf-
folding is that it supports students’ learning of both how to
do the task as well as why the task should be done that way
Scaffolding not only guides learners through the complex-
ities of the task, it may also problematize important aspects
of students’ work in order to force them to engage with key
disciplinary frameworks and strategies (Reiser, 2004). Such
scaffolds act by “rocking the boat” and stopping mindless
PBL AND INQUIRY 101
progress through the task, thus redirecting students’ atten-
tion to important learning goals such as examining counter
claims, articulating explanations and reﬂecting on progress.
Scaffolding is often distributed in the learning environ-
ment, across the curriculum materials or educational soft-
ware, the teachers or facilitators, and the learners themselves
(Puntambekar & Kolodner, 2005). Teachers play a signiﬁ-
cant role in scaffolding mindful and productive engagement
with the task, tools, and peers. They guide students in the
learning process, pushing them to think deeply, and model
the kinds of questions that students need to be asking them-
selves, thus forming a cognitive apprenticeship (Collins et
al., 1989; Hmelo-Silver & Barrows, 2006). In the next sec-
tions, we consider how scaffolding is implemented in PBL
and IL environments.
The Use of Scaffolding in PBL and IL
PBL and IL situate learning in complex tasks. Such task
require scaffolding to help students engage in sense mak-
ing, managing their investigations and problem-solving pro-
cesses, and encouraging students to articulate their think-
ing and reﬂect on their learning (Quintana et al., 2004).
These aspects of IL and PBL tasks are challenging for stu-
dents in many ways, and different researchers aiming to help
learners overcome these conceptual and practical hurdles
have used several scaffolding strategies (e.g., Chinn, 2006;
Guzdial, 1994; Jackson et al., 1996; Linn, Bell, & Davis,
2004; Reiser et al., 2001). Due to space considerations, we
will only discuss a few of these strategies that highlight the
ways in which scaffolding can reduce cognitive load, pro-
vide expert guidance, and help students acquire disciplinary
ways of thinking and acting. All these strategies can support
sense making, process management, and articulation and re-
ﬂection. The examples we present provide a stark contrast
to the Kirschner and colleagues’ argument that inquiry and
PBL environments provide minimal guidance and therefore
increase cognitive load.
Scaffolding That Makes Disciplinary Thinking
and Strategies Explicit
In PBL and IL environments facilitators and teachers make
key aspects of expertise visible through questions that scaf-
fold student learning by modeling, coaching, and eventually
fading some of their support. Student learning occurs as
students collaboratively engage in constructive processing.
For example, in studying an expert PBL teacher in the con-
text of medical education, Hmelo-Silver and Barrows (2006)
showed that the teacher frequently pushed students to ex-
plain their thinking to help them build a causal explanation
or identify the limits of their knowledge. This helps support
students in sense making and in articulating their ideas.
IL and PBL environments also make disciplinary strate-
gies explicit in students’ interactions with the tasks and tools
as well as the artifacts they create (Quintana et al., 2004). For
example, in the scaffolded software tool for analyzing animal
behavior, Animal Landlord, students create a chronological
“storyboard” of the behavioral components they identify in
a short video clip of animal behavior. In creating this sto-
ryboard students are expected to identify behavioral com-
ponents, label them, and annotate their observations and in-
terpretations about these components. This artifact makes
salient the disciplinary strategies of analyzing animal behav-
ior which include decomposing complex behavior into its
constituents, categorizing the constituents, and interpreting
their signiﬁcance (Golan et al., 2001; Smith & Reiser, 1998).
In addition to providing an investigation model for student
to emulate, this also supports students’ sense making and
Many other environments provide students with: (a)
prompts to use particular reasoning strategies (e.g., Derry,
Hmelo-Silver, Nagarajan, Chernobilsky, & Beitzel, 2006;
White & Frederiksen, 1998); (b) structures for students to
follow or ﬁll in, such as ﬁlling in argument diagrams to learn
to distinguish between claims and reasons (Bell, 2002; Toth
et al., 2002) or templates for domain-speciﬁc explanations
(Duncan, 2006; Sandoval & Reiser, 2004); and (c) models
of expert performance for students to emulate (Chinn et al.,
2000; Loh et al., 2001). Chinn and Hung (2007) demon-
strated the effectiveness of expert models in promoting sev-
enth graders’ scientiﬁc reasoning. In a curriculum centered
on argumentation about the interpretation of scientiﬁc stud-
ies, students in some classrooms were presented with models
of children discussing how to evaluate the methodology of
studies with scientists. The participants in these short dis-
cussions engaged in argumentative give and take about the
strengths and weaknesses of studies. Students who received
these models of effective argumentation demonstrated more
individual progress than students who engaged in the same
argumentation-based learning activities without the models.
The models scaffolded students’ reasoning by showing dia-
logic instances of expert reasoning.
Scaffolds That Embed Expert Guidance
In many IL and PBL environments, expert information and
guidance is sometimes offered directly to the learner. For
example in WISE, students are provided with expert’s hints
and explanations of the rationale underlying the processes
students engage in (Davis, 2003). In some cases, such as goal-
based scenarios (Schank & Cleary, 1995), expert information
is offered directly to the learner through “conversations” with
experts in the form of embedded video clips.
Schwartz and Bransford (1998) showed that providing ex-
planations when needed can be a very effective form of scaf-
folding (see also Minstrell & Stimpson, 1996). Schwartz and
Bransford presented some students with a lecture on memory
after they had tried to explain the pattern of results in data
from real memory experiments. Other students received the
102 HMELO-SILVER, DUNCAN, CHINN
lecture without having engaged in the inquiry activity. The
students who received the lecture after trying to explain the
data learned much more from the lecture. In the context of
students trying to explain data, the lecture provided scaffold-
ing that helped students make sense of the data, and hence
was more meaningful than the same lecture presented not as
scaffolding for inquiry but as direct instruction.
In PBL in medical education, the facilitator models a
hypothetical-deductive reasoning process (Hmelo-Silver &
Barrows, 2006). In STELLAR PBL, an adaptation of PBL
to teacher education, preservice teachers use video cases of
expert teachers as models for adapting instructional plans
(Derry et al., 2006). In addition, the video cases are linked to
appropriate concepts in a learning sciences hypermedia. The
indexing of the video to the hypermedia is another form of
Scaffolds That Structure Complex Tasks or
Reduce Cognitive Load
A great deal of structure is provided through scaffolds in
the IL and PBL environments. In PBL, structure is provided
through whiteboards that communicate a problem-solving
process as well through the human facilitator (Barrows, 2000;
Hmelo-Silver, 2004). For example, the whiteboard provides
columns for the group to keep track of the facts of the case,
their evolving hypotheses,thelearning issues, which are con-
cepts that the group needs to learn more about in order to
solve the problem, and an action plan, which helps remind the
group of what they need to do. Maintaining the whiteboard
is a part of the PBL process and becomes a routine that helps
support intellectual discourse. Such routines provide pre-
dictable ways to move through activity structures, set social
norms for participation and use of resources, and foster in-
teraction (Leinhardt & Steele, 2005). Because these routines
become automated, the PBL routine itself reduces cognitive
demands. Although there is initial adaptation required, stu-
dents quickly learn that they need to take on particular roles
and to work together to identify the important facts of the
problem, generate potential ideas about the problems, and
what they need to learn about in order to solve the problem.
Scaffolding can also guide instruction and decrease cog-
nitive load by structuring a task in ways that allow the learner
to focus on aspects of the task that are relevant to the learning
goals (Hmelo-Silver, 2006; Salomon, Perkins, & Globerson,
1991). For example, scaffolding can reduce cognitive load
by automating the generation of data representations, labor
intensive calculations, or storing information. By structuring
the tasks and the available functionality (e.g., in computer-
based environments), scaffolding can restrict the options that
are available to the learner at any point in time to make
the task accessible and manageable (Quintana et al., 2004).
For example in Model-It, a software environment that allows
students to build object-based models of natural phenomena
(such as the effects of pollutants on a stream ecosystem),
there are three functional modes: plan, build, and test (Jack-
son et al., 1996). The software restricts the options avail-
able to students such that students may only proceed to the
build stage after they have planned their models, and they
may not test it until they have identiﬁed some of the impor-
tant objects and relationships in the system. Model-It further
scaffolds students by allowing them to qualitatively express
complex mathematical relationships as the software converts
their verbally stated relationships into mathematical formulas
used for running the model, thereby reducing cognitive load
and situating the task within the learner’s zone of proximal
In summary, many of the types of scaffolding described
provide very strong forms of guidance that seem to us to be
indistinguishable from some of the forms of guidance rec-
ommended by Cognitive Load theorists. We fail to see that
the instruction recommended by Kirschner et al. differs so
clearly from instructional practices in IL methods. Kirschner
et al. touted worked examples and process worksheets as ef-
fective methods of guided learning. But PBL and IL methods
employ modeling that seems very similar to worked examples
as well as scaffolds to guide inquiry that strongly resemble
process worksheets (e.g., Kirschner & Erkens, 2006; White
& Frederiksen, 1998). We think a close analysis of IL and
PBL methods indicates that they are indeed strongly guided
form of instruction. Studies showing that unguided or min-
imally guided instruction is inferior to direct instruction are
simply irrelevant to most approaches implementing PBL or
ARE PBL AND IL INFERIOR TO STRONGLY
GUIDED FORMS OF INSTRUCTION?
It is important to consider learning outcomes as multifaceted.
The goals of learning should include not only conceptual and
procedural knowledge but also the ﬂexible thinking skills and
the epistemic practices of the domain that prepare students
to be lifelong learners and adaptive experts (Bereiter & Scar-
damalia, 2006; Bransford, Brown, & Cocking, 2000; San-
doval & Reiser, 2004). But even on similar outcomes, PBL
and IL often prove to be superior in studies of classroom-
Evidence that PBL is Effective
Although Kirschner et al. (2006) report on several studies and
meta-analyses of PBL, they overlooked other reviews that
were more favorable to PBL. At around the same time as the
Albanese and Mitchell (1993) and Berkson (1993) reviews
that Kirschner et al. (2006) cited, there was a third meta-
analysis conducted by Vernon and Blake (1993). This analy-
sis found that medical students in PBL curricula performed
slightly worse on tests of basic science knowledge but per-
formed better on tests of clinical knowledge than traditional
medical students. In a more recent meta-analysis of the effects
PBL AND INQUIRY 103
of PBL, Dochy, Segers, Van den Bossche, and Gijbels (2003)
found there was no effect of PBL on declarative knowledge
tests, but studies that compared PBL students with those in
traditional curricula on measures of knowledge application
showed a moderate effect size favoring PBL students.
Kirschner et al. cited the results of Patel, Groen, and Nor-
man’s (1993) research. In this study, students from very dif-
ferent universities with different entering characteristics were
compared (and indeed there is a self-selection bias in most
studies of PBL). They were compared at a single time on
a single task, but the PBL students did indeed transfer the
hypothesis-driven reasoning strategy they were taught to new
problems whereas students in a traditional curriculum did not
use this reasoning strategy. The PBL students were also more
likely to make errors. But a close examination of these results
reveals that although the PBL students made more errors,
they also created more elaborated explanations compared to
the sparse explanations of students in the traditional curricu-
lum. Patel et al. concluded (and Kirschner et al. concurred)
that PBL impedes the development of expert data-driven
reasoning strategies. However, other research suggests that
when faced with unfamiliar problems, experts go back to ba-
sic principles and effectively use hypothesis-driven reasoning
rather than the data-driven reasoning used in familiar prob-
lems (Norman, Trott, Brooks, & Smith, 1994). In an experi-
mental study comparing medical students trained to use either
data-driven or hypothesis-driven
reasoning while learning
about electrocardiograms, the hypothesis-driven reasoning
strategy led to superior learning (Norman, Brooks, Colle, &
The accuracy effect found in the Patel et al. study has not
been a robust effect, as the Dochy et al.’s (2003) study sug-
gests. A more recent longitudinal quasi-experimental study
of ﬁrst year medical students found that PBL students gen-
erated more accurate and coherent problem solutions than
traditional medical students (Hmelo, 1998).
Although research at other grade levels and disciplines
outside medicine is rare, there is other work that supports the
positive effects of PBL. Derry et al. (2006) compared preser-
vice teachers in the technology-supported STELLAR PBL
course in educational psychology with students in other sec-
tions of educational psychology on a video analysis transfer
task. Over three semesters of the class, there were consistently
positive effects favoring the students in the PBL class on tar-
geted outcomes. In a carefully controlled crossover study of
MBA students, Capon and Kuhn (2004) randomly assigned
students to either PBL-ﬁrst, lecture-second or lecture-ﬁrst,
PBL-second condition for two different concepts. On mea-
sures of declarative knowledge, there were no differences
between the conditions; however, the students constructed
more integrative explanatory essays for the concepts that
they had learned using a PBL approach.
Data-driven and hypothesis-driven reasoning are also referred to as
forward and backward reasoning, respectively.
PBL has been successfully applied at secondary educa-
tion. In a study comparing traditional and problem-based in-
struction in high school economics, Mergendoller, Maxwell,
and Bellisimo (2006) found that across multiple teachers and
schools, students in the PBL course gained more knowledge
than the students in a traditional course.
Another variant of PBL is anchored instruction, exempli-
ﬁed by the Adventures of Jasper Woodbury used in middle
school mathematics (Cognition and Technology Group at
Vanderbilt [CTGV], 1992). In a large-scale implementation
study comparing students using the Jasper PBL instruction
with matched comparison students across 16 school districts
in 11states, PBL had positive outcomes on standardized tests.
On researcher-developed measures, the results showed no
differences between PBL and traditional math instruction on
single-step word problems but signiﬁcant positive effects on
solving multistep word problems and on other aspects of
problem solving such as planning and problem comprehen-
sion for the PBL group.
The results reported here include fairly traditional mea-
sures of knowledge and knowledge application. It is impor-
tant to note that the goals of PBL go beyond these kinds of
measures. There is evidence that PBL supports the devel-
opment of reasoning skills (e.g., Hmelo, 1998), problem-
solving skills (e.g., CTGV, 1992; Gallagher, Stepien, &
Rosenthal, 1992) and self-directed learning skills (e.g.,
Hmelo & Lin, 2000). PBL methods are also effective
at preparing students from future learning. For instance,
Schwartz and Martin (2004) found that ninth graders who
initially learned through exploratory problem solving em-
ploying statistical principles learned more from a subsequent
lecture than students who had initially learned from a worked
example that the instructor explained in class.
Evidence for Effectiveness of IL Approaches
Kirschner and colleagues asserted that there is a lack of re-
search using controlled experimentation which shows the
relative effectiveness of IL methods. They presented evi-
dence that lower-performing students assigned to minimally
guided instruction showed a decrement in performance fol-
lowing such interventions. It is true that controlled experi-
ments of inquiry-, project-, and problem-based environments
are scarce. However, a few such studies do exist, and those
show signiﬁcant and marked effect sizes and gains in favor
of inquiry-, problem-, and project-based environments (Geier
et al, in press; Hickey, Kindfeld, Horwitz, & Christie, 1999;
Hickey, Wolfe, & Kindfeld, 2000; Lynch, Kuipers, Pyke, &
is an inquiry-based environment that has
been extensively and systematically studied and has been
shown to engender learning gains that are signiﬁcantly larger
than those attained in the comparison classrooms. The Gen-
Scope software is an open-ended inquiry environment de-
signed to support high school students’ investigations of
104 HMELO-SILVER, DUNCAN, CHINN
genetic phenomena (Horwitz, Neumann, & Schwartz, 1996).
Despite its exploratory and open-ended nature the GenScope
environment scaffolds student learning in several comple-
mentary ways: (a) complex simulations make the causal
mechanisms underlying genetic phenomena visible; (b) stu-
dents can easily manipulate representations of biological en-
tities at different biological organization levels; and (c) repre-
sentations of the phenomena at the multiple levels are linked
such that manipulations of one level have consequences (that
students can see) at subsequent levels. Several iterations of
the GenScope environment and related curriculum materials
have been implemented in secondary classrooms and a vali-
dated assessment system was developed to evaluate student
learning (Hickey et al., 2000).
Hickey et al. (1999) found that 381 students in 21 Gen-
Scope classrooms “showed signiﬁcantly larger gains from
pretest to posttest than the 107 students in 6 comparison
classrooms.” The largest gains were attained by students
from general science and general biology classrooms (com-
pared to honors and college prep classrooms). The mean
performance of these students increased from the more basic
forms of domain reasoning (cause-to-effects) to more sophis-
ticated domain reasoning (effect-to-cause). This is contrary
to Kirschner et al.’s argument that IL disadvantages weaker
Particularly impressive are the recent ﬁndings from a
study by Geier et al. (in press), which shows signiﬁcantly
higher pass rates on high-stakes standardized exams for mid-
dle school students (Michigan Educational Assessment Pro-
gram) in science classes that use inquiry-based materials
compared to their peers in a large urban district in the Mid-
western United States. This study involved two cohorts com-
prising 1,803 students in the intervention condition (in 18
schools) and 17,562 students in comparison schools over
three years of enactment. The intervention included up to
three inquiry units, each unit lasting between six and nine
weeks of instruction and focused on concepts in physical sci-
ences and ecology/earth science. These project-based units
scaffolded learning using technology tools that expanded
the types of questions students could investigate, the data
they could collect and provided curricular support for model-
building and scientiﬁc reasoning (Amati, Singer, & Carrillo,
1999; Schneider & Krajcik, 2002; Singer et al., 2000).
Geier et al. (in press) demonstrated that the observed
gains occurred up to a year and a half after participation
in inquiry-based instruction, and the effect was cumulative
such that higher levels of participation (exposure to more
inquiry-based units) resulted in higher gains. The high scores
were attained in all three science content areas (earth, phys-
ical, and life) and both process skills (constructing and re-
ﬂecting) assessed on the test. The effect sizes reported were
0.44 (14% improvement in total score) for students in the
ﬁrst cohort and 0.37 (13% overall improvement) for students
in the larger second cohort. Thus, effect size was not ap-
preciably reduced with the scale-up. Even more compelling
is their ﬁnding that inquiry-based instruction was success-
ful in reducing the achievement gap experienced by urban
African-American boys. African-American boys in the in-
quiry classrooms “caught up” to and showed no statistically
signiﬁcant difference from girls after exposure to at least one
Recent research by Lynch et al. (2005) also suggests that
inquiry-based learning environments foster better engage-
ment and mastery goal orientation among disadvantaged stu-
dents. In their comparison study of over 2,000 eighth grade
students (approximately 1,200 in the treatment and 1,000
in the comparison group) in ten middle schools in a large
and diverse Maryland school district, Lynch et al. (2005)
found overall higher gains for all diversity groupings (based
on ethnicity, socioeconomic status, gender, and ESOL sta-
tus) in the inquiry-based curriculum condition (a six to ten
week unit in chemistry). Thus, inquiry students of all groups
outperformed their comparison peers. The curriculum was
also more effective (than traditional instruction) in increas-
ing certain aspects of motivation and engagement, particu-
larly among historically disadvantaged student groups.
There are other studies that we interpret as supporting
the effectiveness of IL and other constructivist environments
(e.g., Guthrie et al., 2004; Langer, 2001; Wu & Tsai, 2005).
For example, Guthrie et al. found that an elementary school
reading program that combined strategy instruction with en-
hanced student choice, ample hands-on experiences, and
substantial student collaboration was more effective at ad-
vancing students’ reading than either traditional instruction
or a strategies-instruction-only treatment. We suspect that
Kirschner et al. might claim that this study supports their
position, because teachers who used the reading program
provided students with guided instruction on strategies. If
they did make this claim, they would only reinforce our cen-
tral point. What Kirschner et al. view as effective instruction
is often fully compatible with IL and other constructivist in-
struction. Most proponents of IL are in favor of structured
guidance in an environment that affords choice, hands-on
and minds-on experiences, and rich student collaborations.
In conclusion, there is growing evidence from large-scale
experimental and quasi-experimental studies demonstrating
that inquiry-based instruction results in signiﬁcant learning
gains in comparison to traditional instruction and that disad-
vantaged students beneﬁt most from inquiry-based instruc-
tional approaches. In many or most cases, exemplars of IL
instruction incorporate strong forms of guidance that propo-
nents of guided instruction will ﬁnd attractive.
Goals for Learning and Instruction
Kirschner et al. (2006) claimed that the pursuit of inquiry-
based instructional methodologies has resulted in a shift of
instructional focus “away from teaching a discipline as a body
of knowledge towards an exclusive emphasis on learning a
discipline by experiencing the processes and procedures of
PBL AND INQUIRY 105
the discipline.” This claim is problematic for at least two rea-
sons. First, the change in instructional focus is not merely
a result of inquiry methods of instruction but rather a much
broader call for reform in the goals of education. Recent re-
form documents (AAAS, 1993; NCTM, 2000; NRC, 1996),
in the United States as well as other countries (DFE/WO,
1995; Ministry of Education [Taiwan], 2001), have empha-
sized the importance of understanding not only content but
also disciplinary epistemologies and investigative strategies.
In the case of science education in particular, a large body of
research supports the importance of understanding the nature
of scientiﬁc research and the practices involved as a critical
part of scientiﬁc literacy (e.g., DeBoer, 1991; Driver, Leach,
Millar, & Scott, 1996; Duschl, 1990; Lederman, 1998; Mc-
Comas, Clough, & Almazroa, 1998). This suggests broad
goals for learning and instruction.
Second, current reforms and the inquiry approach are not
substituting content for practices; rather, they advocate that
content and practices are central learning goals. IL models
do in fact foster rich and robust content learning (Shyman-
sky, 1984; Wise & Okey, 1983; Von Secker & Lissitz, 1999).
While it is challenging to develop instruction that fosters the
learning of both the theoretical frameworks and investigative
practices of a discipline, examples of such environments do
exist (Linn, Bell, & Hsi, 1999; Reiser et al., 2001; White &
Frederiksen, 1998), and recent design frameworks offer guid-
ance for the development of such rich learning environments
(Edelson, 2001; Quintana et al., 2004).
The notion that learning the concepts and theories of a dis-
cipline is best situated in the context of the practices of that
discipline is supported by current theories of learning. Both
situated and cognitivist perspectives on cognition recognize
the inﬂuence of the learning context on the accessibility of
the knowledge for future use (Collins, Brown, & Newman,
1989; Greeno, 2006; Kolodner, 1993; Schank, 1982). Given
that students need to develop scientiﬁc understandings as in-
terconnected, meaningful, and useful, it is imperative that the
learning environments in which students acquire this knowl-
edge be similar to its likely context of use. These likely ap-
plication contexts are situations in which students will face
ill-deﬁned problems such as evaluating scientiﬁc ﬁndings and
arguments presented in the media, determining the beneﬁts
and risks of policies (or health procedures) through research
and investigation, and constructing logical and scientiﬁcally
sensible explanations of everyday phenomena. It follows then
that learning situations should provide students with oppor-
tunities to engage in the scientiﬁc practices of questioning,
investigation, and argumentation as well as learning content
in a relevant and motivating context.
Even in this limited review of research on PBL and IL, it
is clear that the claim that PBL and IL “does not work” is
not well supported, and, in fact, there is support for the al-
ternative. But we would argue that “Does it work?” is the
wrong question. The more important questions to ask are un-
der what circumstances do these guided inquiry approaches
work, what are the kinds of outcomes for which they are
effective, what kinds of valued practices do they promote,
and what kinds of support and scaffolding are needed for
different populations and learning goals. The questions that
we should be asking are complex as is the evidence that
might address them. It requires one to also consider the goals
of education—including not only learning content but also
learning “softer skills” (Bereiter & Scardamalia, 2006) such
as epistemic practices, self-directed learning, and collabora-
tion that are not measured on achievement tests but are impor-
tant for being lifelong learners and citizens in a knowledge
society. In many ways, we do not yet have adequate answers
to these questions concerning the conditions under which
various types of scaffolded learning environments are most
effective. While we are not arguing against various forms of
direct and more heavily guided instruction, of the sort that
Kirschner et al advocate, it is still unclear how to balance
IL and PBL (which are more constructivist and experiential)
with direct instructional guidance. We believe that more di-
rected guidance needs to build on student thinking. As a ﬁeld
we need to develop deeper and more detailed understandings
of the interrelationships between the various instructional ap-
proaches and their impact on learning outcomes in different
We wish to conclude this article with the common wisdom
of Confucius on the nature of instruction and human learning:
“Tell me and I will forget; show me and I may remember;
involve me and I will understand.” We argue that IL and PBL
approaches involve the learner, with appropriate scaffolding,
in the practices and conceptualizations of the discipline and in
this way promote the construction of knowledge we recognize
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