Data Mining -> Systems Factors  -> Test Score vs Class Size - California

What happens when class-size reduction is implemented to scale?

Why is this question important? Billions of dollars are spent each year to fund smaller class sizes with the expectation that this will improve student achievement. These data suggests that this investment may not have had a large impact on California's students' learning.

See further discussion below.

Source: Class Size Reduction in California: Early Evaluation Findings, 1996-1998, Technical Report, June 1999, pg. xix, Fig. 7. http://www.classize.org/techreport/execsum.html 

Results: While California students' test scores generally improved during the period when class sizes were reduced, only a small improvement can be attributed to reduced class size. California's implementation of class-size reduction did not mirror that of the Tennessee STAR Project. In California the achievement gains of students were minimal, improvement for low socio-economic students did not occur as anticipated, and the costs of implementation had a major impact on the state's education budget.

Implications: This data suggests obtaining increased student achievement through smaller classes may be much more complex than initially predicted.
Research-to-Practice: 1. The effect size achieved in the STAR Project was notable, ranging from .17 to .34 in the early grades. California’s implementation of class-size reduction occurred quickly, without the forethought that may have been required, and was accomplished on an extraordinary scale.  It was reasonable to anticipate a certain reduction in effect be experienced due to the less than systematic manner in which class-size reduction was implemented. 2. California deviated from the STAR Project intervention when it established a classroom size of 20 students. STAR Project results were achieved through a classroom ratio of 13-17 students. There is no agreement as to the optimal class size. The STAR Project identified that positive results begin to decline for class-sizes greater than 17. Other studies suggest that the greatest gains occur as class-size approaches 15 or lower.
Implementation: There are serious issues in the implementation of any intervention. It has been said that, "Implementation is where great ideas go to die". The scale of California's experiment in class-size reduction was unprecedented. The logistics alone had the potential to derail the plan.  In hind-sight it is clear that  California was unprepared for such a monumental re-engineering of the education system. 1. The state did not provide for the increase in qualified personnel needed to fill the many new teacher openings required of the change in ratios. 2. The state did not provide for the impact on facilities from the increase in the classrooms needed as a result of reducing class-sizes.
Cost: The initial price tag to the State of California was approximately $1 Billion and these costs rose in the second year to over $1.6 Billion. These expenses did not include other substantial outlays that districts were not reimbursed by the state. Under any analysis, class-size reduction is a very expensive proposition.
Lessons learned: 1. Make sure that the benefits that are anticipated from an intervention are worth the time, money, and effort that will be required to implement the change. 2. When taking a major intervention to scale, time should be invested conducting an analysis into responding to potential obstacles and complications that may hinder implementation. 3. Do not inflate potential results. Assure effectiveness studies have been conducted and the conditions under which the intervention works are well understood.

Authors:  Class Size Reduction Consortium; American Institutes for Research (AIR), RAND, Policy Analysis for California Education (PACE), WestEd, Resource

Publisher: Class Size Reduction Consortium

Study Description: The CSR Research Consortium was contracted by the California Department of Education to evaluate the implementation and impact of California's class size reduction initiative that began in July 1996. The study concluded in September 2002. Reduced size classes were defined to be less than 20 students, whereas non-reduced classes averaged 29 students. CSR collected data from California schools and evaluated how reduced size classes affected many aspects of the education system in California. The Stanford Achievement Test, version 9 (SAT-9) results were used to evaluate student performance in various subjects. A good deal of effort was spend separating the effects of several other changes in California education implementation during the same period from those of the class size reduction.

Definitions:
SAT-9 = Stanford Achievement Test, version 9

Citation:
Bohrnstedt, G. W., & Stecher, B. M. (Eds.) (1999). Class size reduction in California: Early evaluation findings, 1996-1998. Palo Alto: CSR Research Consortium, Year 1 Evaluation Report, American Institutes for Research.

Related Research: The State of Tennessee's Student/Teacher Achievement Ratio (Star) Project: K-3 Class-Size Study