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A best-evidence synthesis of research on acceleration options for gifted students

Gifted Research

This article by Karen Rogers examines 12 forms of acceleration. The author discusses research results from 314 studies with positive effects. The results show that there were positive findings for socialization effects from grade skipping, mentorships and positive psychological adjustment effects for concurrent enrollment and mentorships.

Author: Rogers, K.
Publisher: Trillium Press
Year: 1992

The research on 12 forms of acceleration was synthesized using Slavin’s “best-evidence synthesis” procedure. The Effect Sizes for academic, socialization, and psychological outcomes were calculated for each study containing adequate data, then averaged across all studies pertaining to each accelerative option. Of the 314 studies located covering the years from 1912-1988, only 81 studies provided enough data for calculating Effect Sizes. Significant academic effects were found for all but three options: Concurrent Enrollment, Advanced Placement, and Combined Accelerative Options. In general, the research showed no substantial positive or negative socialization and psychological effect differences for most forms of acceleration. However, two significant positive socialization Effect Sizes were found for Grade Skipping and Mentorships; likewise, two significant positive psychological adjustment effects were found for Concurrent Enrollment and Mentorships

In the past 15 years there has been increasing interest in educational practices for the gifted learner. An informal count of the related publications, listed by Educational Resources Information Center (ERIC) during this 15-year period indicated a 400 percent rise in the number of articles written, as compared to the 15-year period before then. Although frequency counts may indicate more awareness and involvement in the area of gifted studies, there is some concern about the quality of research published in this field (Jenkins-Friedman, 1986). Reputedly, the majority of these studies have consisted of relatively weak research designs and an overabundance of “how to” articles with inadequate research-based support. Clark (1988), among others, has argued, however, that within the past few years technology has vastly improved the ability of researchers to characterize and analyze the learning process more accurately, which has led to a better understanding of giftedness and intellectual ability.

Educational acceleration as a curricular option has been a divisive issue among educators since its first documented implementation in the St. Louis, Missouri Schools in 1862. Since 1933 at least 26 reviews of research have been conducted on acceleration. Although previous reviews of the outcomes of acceleration have been consistently positive among researchers, perceptions of its efficacy have been markedly negative among practitioners and school administrators. Kulik and Kulik (1984), in particular, used the procedure of meta-analysis to quantify the general effects of two general forms of acceleration (“curriculum compression” and “other”), concluding that gifted accelerates gained almost nine-tenths of a grade equivalent school year over their gifted, same-age peers who were not accelerated and were no different in their academic performance than their gifted older-aged classmates (ES=+.05). Although the Kuliks clarified the general effects of acceleration in terms of its academic outcomes, some concerns have been raised about the forms of acceleration that were combined in their synthesis. Unanswered also was the question of what happens to the social and emotional development of the gifted accelerates: Do they withdraw and become uncertain of their abilities or blossom once cognitive challenge has been provided? Even with general quantitative effects established by the Kuliks’ landmark study, acceleration remains a relatively unused educational practice. In an effort to understand why such remarkable differences of opinion continue to exist between theoretical and practical perspectives, this exhaustive analysis of research-based studies of acceleration was undertaken. The problem in this study, therefore, became how to objectively, systematically, and quantitatively describe the content of the research on accelerative programming options for gifted students produced from 1929 to 1988, the period for which educational research has been complied systematically in indices.

A search of ERIC, Exceptional Children’s Education Resources (ECER), and the Dissertation Abstracts Index (DPI) databases, manual searches of Current Index to Journals in Education (CITE) and Resources in Education (RIE), and branching from study reference lists and review bibliographies were used to collect extant research. All studies involving the systematic collection of data about some form of accelerated practice were then categorized by type of accelerative option. Twelve forms of acceleration were identified: (1) Early Entrance to School (EE); (2) Grade Skipping (GS); (3) Nongraded Classrooms (NG): (4) Curriculum Compaction (CC); (5) Grade Telescoping (GT); (6) Concurrent Enrollment (CE): (7) Subject Acceleration (SA); (8) Advanced Placement (AP); (9) Mentorship (ME); (10) Credit by Examination (EX); (11) Early Admission to College (EA); and (12) Combined Accelerative Options (CE).

Using Slavin’s (1985, 1987) “best-evidence synthesis” technique, the studies within each acceleration category were rank ordered by strength of study design and sample size. The outcomes for each study were classified as: (1) academic (A), which included standardized achievement scores, teacher. developed test scores, grade averages, teacher ratings of student performance, and attitude toward learning; (2) socialization (5), which included social maturity scores, teacher ratings of social skills, participation in extracurricular activities, and leadership positions held; and (3) psychological adjustment (P), which included self-concept inventory scores, teacher/parent ratings of esteem, risk-taking, independence, and creativity ratings. Separate Mean Effect Sizes were calculated for each type of outcome for each study. The general formula for Effect Size (ES) was M e – M c I s c, where M represents the mean score of the experimental (e) or control (c) group and a represents the standard deviation of the control group. When more than one academic, socialization, or psychological outcome was reported in a single study, all outcomes of that type were averaged together. The Mean Effect Sizes for all studies in an acceleration category were then subjected to the fledges and 01km (1985) Q-test for the homogeneity of K data items to ensure that there were no outliers among the studies combined for effect. When outliers were found, these studies were omitted from the calculation of Median Effect Size across all studies of one form of acceleration. Using this procedure, Median Effect Sizes were calculated for each type of outcome (A,S,P) for each form of acceleration.

Analyses by period of publication (three periods: 1912-1940; 1941-1965; 1966-1988), general type of acceleration (three types: subject-based; grade-based; college-based), and by grade level (four levels: primary [K-3], intermediate [4-6], junior high [7-9], senior high [10-12]) were also conducted.

As Table One shows, significant academic effects (ES > +.30) were found for all but three options (CE, AP, GB). Two significant socialization Effect Sizes were found (OS, ME), as were two significant psychological Effect Sizes (CE, ME). No studies were located for socialization outcomes of NG, CC, SA, and EX, or for the psychological effects of CC, GT, and EX.

Table 1. Effects Table of Academic, Socialization, and Psychological Outcomes for 12 Forms of Acceleration for Gifted Students*

Analysis by period of publication found a general decline in Effect Size for more recent studies (1966-1988). Analysis by general type of acceleration revealed a significant academic effect (ES = +.46) for grade-based acceleration (EE, GS, GT, NG), significant academic (ES = +.49) and psychological (ES = +.58) effects for subject-based acceleration (CC, SA, CE, ME), and significant academic effect (ES = +.38) for college-based acceleration (AP, EX, CE, EA). Analysis by grade level revealed significant academic effects for all forms of acceleration at each level: ES (primary) = .64; ES (elementary) = +.59; ES (Junior high) = +.34; ES (senior high) = +.31.

Table 1.
Effects Table of Academic, Socialization, and Psychological Outcomes for 12 Forms of Acceleration for Gifted Students.

Option Academic ES Socialization ES Psychological ES
EE .36 .12 .14
GS .78 .46 .12
NG .38 .02 .11*
CC 1.48 (.45)**
GT .56 .22 -.06*
CE .16 .05 .74 (.36)**
SA 1.02 (.49)** -.16
AP .29 .24* .07*
ME .42 .50 (.01)** .48
EX .75
EA .44 -.06 .11
CB .15 -.03 .16*

* Based on 1 study
** 1 study may have overly influenced outcomes. 2nd # has study removed.

A general pattern of positive academic effects was obtained for most accelerative options, while some questions were raised about the limitations of the academic measures used for the three options which did not obtain Effect Sizes greater than +.30, the level of “practical significance” recommended by meta-analysts (Glass, McGaw, & Smith, 1981; Slavin, 1987; Kulik & Kulik, 1984; Glass, 1976). Although some significant effects were found for the socialization and psychological adjustment outcomes for some forms of acceleration, much about socialization and psychological effects remains unstudied. Such outcomes must be studied, in particular, for Nongraded Classrooms, Curriculum Compaction, Subject Acceleration, Credit by Examination, and Grade Telescoping.

It is thought that this study laid to rest misconceptions that: (1) acceleration is primarily grade skipping; and (2) acceleration produces negative social and emotional consequences for gifted learners. It is believed that as a result of this study educational decision-makers have been offered a fairly well substantiated, research-supported menu of accelerative options that result in significant academic achievement gains. If there is concern with the lack of general change found for socialization and psychological adjustment when the majority of these accelerative options are implemented, perhaps a school counselor or small-group affective support groups might be considered to enhance outcomes in those areas for the accelerants.


Clark, B. (1988). Growing up gifted: Developing the potential of children at home and at school. Columbus, OH: Charles E. Merrill Publishing Company.

Glass, G.V. (1976). Primary, secondary, and meta-analysis of research. Educational Researcher, 5(10), 3-8.

Glass, G.V., McGaw, B., & Smith, M.L. (1981). Meta-analysis in social research. Beverly Hills, CA: Sage.

Hedges, L.V., & Olkin, I. (1985). Statistical methods for meta-analysis. Orlando, FL: Academic Press, Inc.

Jenkins-Friedman, R.J. (1986). Standing on the shoulders of giants. Gifted Child Quarterly, 30, 3-4.

Kulik, J.A., & Kulik, C-L.C. (1984). Effects of accelerated instruction on students. Review of Educational Research, 54, 409-425.

Slavin, R.E. (1986). Best-evidence synthesis: An alternative to meta-analytical and traditional reviews. Educational Researcher, 9 (15), 5-11.

Slavin, R.E. (1987). Ability grouping: A best-evidence synthesis. Review of Educational Research, 57, 293-336.

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