With the release of the National Science Education Standards, the issues of why, how, and what we, as teachers, assess in our classrooms will become a major challenge in the multifaceted science reform effort currently underway. As educators are changing their ideas about what constitutes exemplary inquiry-based learning, and recognizing that science is an active process that encourages higher-order thinking and problem solving, there is an increased need to align curriculum, instruction, and assessment. Classroom assessment techniques are focusing on aligning assessments more closely with the instructional strategies actually used with children.

The Nature of Assessment

Assessment can be defined as a sample taken from a larger domain of content and process skills that allows one to infer student understanding of a part of the larger domain being explored. The sample may include behaviors, products, knowledge, and performances. Assessment is a continuous, ongoing process that involves examining and observing children's behaviors, listening to their ideas, and developing questions to promote conceptual understanding. The term authentic assessment is often referred to in any discussion of assessment and can be thought of as an examination of student performance and understanding on significant tasks that have relevancy to the student's life inside and outside of the classroom.

The increasing focus on the development of conceptual understanding and the ability to apply science process skills is closely aligned with the emerging research on the theory of constructivism. This theory has significant implications for both instruction and assessment, which are considered by some to be two sides of the same coin. Constructivism is a key underpinning of the National Science Education Standards.

Constructivism is the idea that learning is an active process of building meaning for oneself. Thus, students fit new ideas into their already existing conceptual frameworks. Constructivists believe that the learners' preconceptions and ideas about science are critical in shaping new understanding of scientific concepts. Assessment based on constructivist theory must link the three related issues of student prior knowledge (and misconceptions), student learning styles (and multiple abilities), and teaching for depth of understanding rather than for breadth of coverage. Meaningful assessment involves examining the learner's entire conceptual network, not just focusing on discreet facts and principles.

The Purpose of Assessment

Critical to educators is the use of assessment to both inform and guide instruction. Using a wide variety of assessment tools allows a teacher to determine which instructional strategies are effective and which need to be modified. In this way, assessment can be used to improve classroom practice, plan curriculum, and research one's own teaching practice. Of course, assessment will always be used to provide information to children, parents, and administrators. In the past, this information was primarily expressed by a "grade". Increasingly, this information is being seen as a vehicle to empower students to be self-reflective learners who monitor and evaluate their own progress as they develop the capacity to be self-directed learners. In addition to informing instruction and developing learners with the ability to guide their own instruction, assessment data can be used by a school district to measure student achievement, examine the opportunity for children to learn, and provide the basis for the evaluation of the district's science program. Assessment is changing for many reasons. The valued outcomes of science learning and teaching are placing greater emphasis on the child's ability to inquire, to reason scientifically, to apply science concepts to real-world situations, and to communicate effectively what the child knows about science. Assessment of scientific facts, concepts, and theories must be focused not only on measuring knowledge of subject matter, but on how relevant that knowledge is in building the capacity to apply scientific principles on a daily basis. The teacher's role in the changing landscape of assessment requires a change from merely a collector of data, to a facilitator of student understanding of scientific principles.

The Tools of Assessment

In the development and use of classroom assessment tools, certain issues must be addressed in relation to the following important criteria.

A. Purpose and Impact— How will the assessment be used and how will it impact instruction and the selection of curriculum?
B. Validity and Fairness— Does it measure what it intends to measure? Does it allow students to demonstrate both what they know and are able to do?
C. Reliability— Is the data that is collected reliable across applications within the classroom, school, and district?
D. Significance— Does it address content and skills that are valued by and reflect current thinking in the field?
E. Efficiency— Is the method of assessment consistent with the time available in the classroom setting?

There is a wide range of assessments that are available for use in restructuring science assessment in the classroom. These types of assessments include strategies that are both traditional and alternative. The various types of alternative assessments can be used with a range of science content and process skills, including the following general targets.

Declarative Knowledge— the "what" knowledge

Conditional Knowledge— the "why" knowledge

Procedural Knowledge— the "how" knowledge

Application Knowledge— the use of knowledge in both similar settings and in different contexts

Problem Solving— a process of using knowledge or skills to resolve an issue or problem

Critical Thinking— evaluation of concepts associated with inquiry

Documentation— a process of communicating understanding

Understanding— synthesis by the learner of concepts, processes, and skills

Assessment can be divided into three stages: baseline assessment, formative assessment, and summative assessment. Baseline assessment establishes the "starting point" of the student's understanding. Formative assessment provides information to help guide the instruction throughout the unit, and summative assessment informs both the student and the teacher about the level of conceptual understanding and performance capabilities that the student has achieved. The wide range of targets and skills that can be addressed in classroom assessment requires the use of a variety of assessment formats. Some formats, and the stages of assessment in which they most likely would occur, are shown in the table.

ASSESSMENT FORMATS
Format	Nature/Purpose	Stage
Baseline Assessments	Oral and written responses based on individual experience Assess prior knowledge	Baseline
Paper and Pencil Tests	Multiple choice, short answer, essay, constructed response, written reports Assess students acquisition of knowledge and concepts	Formative
Embedded Assessments	Assess an aspect of student learning in the context of the learning experience	Formative
Oral Reports	Require communication by the student that demonstrates scientific understanding	Formative
Interviews	Assess individual and group performance before, during, and after a science experience	Formative
Performance Tasks	Require students to create or take an action related to a problem, issue, or scientific concept	Formative and Summative
Checklists	Monitor and record anecdotal information	Formative and Summative
Investigative Projects	Require students to explore a problem or concern stated either by the teacher or the students	Summative
Extended or Unit Projects	Require the application of knowledge and skills in an open-ended setting	Summative
Portfolios	Assist students in the process of developing and reflecting on a purposeful collection of student-generated data	Formative and Summative

It is clear that different kinds of information must be gathered about students by using different types of assessments. The types of assessments that are used will measure a variety of aspects of student learning, conceptual development, and skill acquisition and application. The use of a diverse set of data-collection formats will yield a deeper and more meaningful understanding of what children know and are able to do, which is, after all, the primary purpose of assessment.