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Most children acquire an understanding of the natural world well before they receive their first science lesson, research suggests. They know that solid objects cannot move through each other, that individuals behave differently, and that plants and animals need food to live.

After enrolling in school, that knowledge is broadened and refined, experts say, as students face society鈥檚 expectations for what they need to know about science, for each grade.

Developing a cohesive, logical path between those starting and ending points is the goal of 鈥渓earning progressions,鈥� a concept that has long interested scholars and soon could draw renewed attention from school officials, particularly when it comes to teaching science.

Learning progressions are frameworks that spell out how student comprehension of concepts should grow over time. Those progressions, scholars say, should be guided by an understanding of how children learn and the knowledge that they already possess or have been taught.

Despite scholarly work on progressions, the concept is unfamiliar in the vast majority of K-12 school systems in the United States, where states and schools have been reorganizing lessons around academic standards and mandatory tests since the late 1980s.

But some researchers believe the approach could gain support as school leaders seek more effective ways of teaching science, with the goal of improving achievement in that subject and producing more students capable of pursuing advanced scientific studies and careers.

A report released last month by the congressionally chartered National Research Council, in Washington, pointed to learning progressions鈥� potential as a more orderly, less scattershot way of teaching science in grades K-8. (鈥淧anel Points Way to Improving K-8 Science Learning,鈥� Sept. 27, 2006.)

鈥淲e see missed opportunities鈥攚ays that the learning of science has been compartmentalized,鈥� said Brian J. Reiser, a professor of learning sciences at Northwestern University, in Evanston, Ill., and a member of the committee that produced the NRC report. 鈥淭he idea behind learning progressions is, let鈥檚 figure out a sensible path. We may not use the same path for everyone, but let鈥檚 figure out a logical path.鈥�

Connected Steps

Studies of learning progressions, sometimes referred to as 鈥渃ontinua,鈥� date back at least as far as the 1980s. Researchers have explored the potential benefits of progressions within many academic subjects and skills, particularly in literacy.

Experts on learning progressions see them as distinct from academic standards or curricula. Standards, such as those set forth by individual states, are expectations for what students should know, with different demands at each grade level. Learning progressions, supporters say, instead describe growth in student understanding over time, drawing connections between the intermediate steps at each grade level.

With academic standards, 鈥測ou often see no relation between grades 3 and 4. They鈥檙e separate pieces of information,鈥� said Margaret Forster, a research director at the Australian Council for Educational Research, located near Melbourne, who has studied progressions extensively. Learning progressions, she said, are meant to 鈥渋llustrate the growth, and how topic one builds on another.鈥�

Nor are learning progressions supposed to promote certain types of pedagogy, or teaching methods. Teachers should be free to try a number of approaches in using progressions, as long as they promote 鈥減rogressively more sophisticated ways of thinking about a topic,鈥� said Carol L. Smith, an associate professor of psychology at the University of Massachusetts Boston.

鈥淲e鈥檙e not in any way saying there is one, monolithic way to do it,鈥� said Ms. Smith, whose research is cited in the NRC study.

Learning progressions are an alternative to students鈥� simply learning a 鈥渓itany of facts,鈥� she said, without understanding how they connect to one another. That was a major theme of the NRC study, which maintains that science instruction in the United States presents topics in an incoherent, disconnected way, with major concepts and less essential ideas receiving equal weight.

鈥淭opics receive repeated, shallow coverage with little consistency,鈥� the report asserts, 鈥渨hich provides a fragile foundation for further knowledge growth.鈥�

Progress Down Under

A better alternative, the authors say, is for schools to focus more clearly on 鈥渂ig ideas鈥� of science, which students can concentrate on in greater depth. Learning progressions are an especially promising method for reinforcing students鈥� understanding big ideas for several reasons, researchers say. They are grounded in current research on how students learn, and they encourage students to approach a scientific topic in several different ways, returning to it repeatedly and building on that knowledge.

By re-emphasizing important topics, learning progressions also help correct common misconceptions about science that students often bring to school, Ms. Smith argued.

The NRC report does not catalog the 鈥渂ig ideas鈥� schools should focus on鈥攖hat should be the subject of future research, its authors say鈥攂ut it gives a few examples. One such concept is the theory of evolution. Another is atomic-molecular theory, or the study of atoms and molecules and their behavior.

The NRC study offers an example of a typical learning progression for that topic, showing how students in K-2 should develop a basic understanding that objects have certain properties, such as weight and volume, and, by grades 6-8, understand the definition of mass, and its relation to weight and gravitational fields, among other ideas.

For years, Ms. Forster has created 鈥減rogress maps鈥� or descriptions of learning progressions, for students in Australia, in reading, math, science, and other subjects. Several experts cite her work as having strongly influenced thinking among scholars in the United States on how progressions can work. National, state, and district governments in Australia have used Ms. Forster鈥檚 progress maps, and her organization has also advised officials in foreign countries, including Chile and the Philippines, in developing their own.

Ms. Forster鈥檚 organization produced progress maps in reading, speech, listening, and other areas based on an analysis of a 1996 nationwide literacy survey financed by the Australian government. Government officials there described the lackluster literacy results as 鈥渁 national disgrace鈥�; the progress maps were generated as a way of setting clearer descriptions of crucial skills.

The progress map in speech describes five skill levels. At the most basic level, pupils should be able to express simple ideas, even if they convey limited meaning, and present stories, even if they are 鈥渄isjointed or incomplete.鈥� At level 2, they should be able to tell a story with a plot, include key information, and offer opinions, even if they are not justified views.

At level 3, students should be able to show evidence of organization in their speech, justify their opinions, and give key ideas about characters, experiences, and events. Level 4 skills include the ability to present a strong point of view, and make a complete, well-organized presentation. And at level 5, students should be able to combine the use of appropriate language, the presentation of challenging ideas, and organization into a well-reasoned speech, according to the progress map.

How Detailed?

The challenge in producing progress maps is knowing 鈥渉ow much detail do you go into,鈥� Ms. Forster said in an interview. Early versions of maps she designed 鈥渨ere so detailed, there was no making sense of them,鈥� she recalled.

Ms. Forster鈥檚 organization has developed three posters showing progress maps in reading, writing, and spelling, which were distributed by the national government to primary schools across Australia. Since publishing them, she said, school administrators have told her they found the maps useful in making academic goals for various subjects clear to teachers, students, and parents.

Understanding cognition鈥攐r how students learn鈥攊s essential to creating an effective learning progression, researchers say. Many students, for instance, arrive in kindergarten with the ability to distinguish between objects and materials, and make observations about them, the NRC study notes. Those early skills鈥攐ften overlooked by educators鈥攃an prove valuable for teachers in building student understanding of scientific measurement, according to the report.

By contrast, educators and others should avoid the assumption that students are not cognitively capable of understanding a concept by a certain grade or age, said Mr. Reiser of Northwestern University. Students鈥� struggles at one level of a learning progression may be the result of their not having been taught the material the year before, or not having been exposed to it before starting school.

鈥淚t鈥檚 not an argument that 4th graders鈥� brains can鈥檛 do that,鈥� Mr. Reiser cited as an example. 鈥淚t鈥檚 that the progressions haven鈥檛 prepared them for that. 鈥� It鈥檚, 鈥榃hat would the progression be in 1st, 2nd, and 3rd grade to prepare them for that?鈥� 鈥�