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Cbnrcnl f&~lo~ Rrwu,, Vol. 11,

pp.

397-369. 1991

Printed in the USA. 411 rights reserved.

0272.7358191 3.00 + .OO

Copyright 0 1991 Pergamon Press plc

THE EFFICACY OF

RATIONAL EMOTIVE THERAPY:

A QUANTITATIVE REVIEW OF

THE OUTCOME RESEARCH

La rry C Lyo ns

Pa ul J Wo od s

Hollins ollege

ABSTRACT

The results from a meta-analysis of 70 Rational-Emotive Therapy (RET)

outcome studies are reported. A total of 236 comparisons of RET to baseline, control groups,

Cognitive Behavior Modification, Behavior Therapy, or other psychotherapies are examined.

The results indicate that subjects receiving RET demonstrated significant improvement over

baseline measures and control groups. Eff t-

c size was significantly related to therapist

experience and to duration of the therapy, but there were no significant differences in

effect-size between those studies that used psychotherapy clients compared to those using

students as subjects. Those comparisons that were rated high in internal validity {random

assignment, low attrition, and outcome measures low in reactivity), had significantly higher

effect-sizes than medium validity studies. Outcome measures rated as low in reactivity (i.e.,

those measures which did not have an immediately discernable relationship with the

treatments being assessed) had significantly higher effect-sizes than more reactive measures.

Contrary to other reviews using the narrative review method, RET was found to be an

effectizre form of therapy. This conclusion, however, was tempered by methodological f la ws in

the studies reviewed, such as lack of follow-up data and information regarding attrition

rates.

We thank Ms. Wendy A. Morris for her assistance in preparing this manuscript.

Larry C. Lyons, MA, is a Research Associate at the Hollins Communications Research

Institute. Paui J. Woods, PhD, is a Professor of Psychology at Hollins College, a Licensed

Psychologist in private practice, and a Fellow of the Institute for Rational-Emotive

Therapy.

Correspondence and reprint requests of this article, coding manual, or list of studies used

in this quantitative review should be addressed to Paul J. Woods, P.O. Box 9655, Hollins

College, Roanoke, VA 24020.

357

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358

L. C. Lyons nnd P. J. Woods

Reviews of outcome studies of Rational-Emotive Therapy (RET) have been

published on a number of occasions. The most recent was that by Haaga and

Davison (1989), which reviewed a number of studies classified by the nature of the

problem or disorder under treatment. This review also included an adaptation of

RET, Rational-Emotive Education, and a variant of RET, Systemat,ic Rational

Restructuring. The studies were organized according to general problems, stress

reduction, various categories of anxiet.y disorders, assertiveness, headaches. stut-

tering, psychosexual dysfunctions, Type A Behavior Pattern, anger, obesity,

depression, and antisocial behavior. In commenting upon this review, Ellis (1989)

noted that it is probably the most comprehensive review of this area that has yet

been done

(p.

228). Even so, large numbers of dissertations and published studies

were omitted from the review. More importantly, Ellis (1989) argued, many of the

outcome studies utilized only one of RETs main features, that of cognitive

restrLlcturing or systematic rational l-estrLlct~lring. But even with just this one

aspect of RET being studied, many clinically important effects were found.

This most recent review has been preceded by a number of others, some large

and some small. McGovern and Silverman (1984) reviewed 47 RET outcome

studies that were published since an earlier comprehensive attempt (DiCiuseppe &

Miller, 1977). This earlier review covered 22 studies. Other reviews of outcome

studies include Ledwidge (1978)

(

rr = t?), Prochaska (1984) (~2 = 81, and Zettle

and Hayes (1980) (71 = 16).

For the most part, despite a variety of methodological problems, the aspects of

RET that have been studied generally hold up as being effective for therapeutic

and educational interventions. All of these previous reviews, however, have been

q~u~~tat~zlein nature.

In contrast, the present review examines the efficacy of RET

with the qua?7t~tut~~e review method of meta-analysis and addresses many of the

criticisms advanced by previous reviews of RET.

METHODS

Selection

of

tud ies

Psychological Abstracts and Dissertation Abstracts International from 1972 to 1988 were

searched for relevant studies. Also, the references in the obtained studies and the

previously mentioned reviews were scanned for additional material. A list of

studies used in this meta-analysis is available on request.

Each study was required to meet the following criteria for inclusion in the

present review:

1. At least one treatment group received Rational-Emotive Therapy, or a

treatment which used elements of RET.

2. The study compared RET to a baseline measure, a control group, or other

type of therapy.

A

complete

list of the articles and dissertations, and the coding manual used in the present

meta-analysis is available from the second author for a $5 fee to cover printing, postage,

and handling. A BASIC program (in both MAC and MS-DOS formats) for coding the study

data, converting the individual study statistics,

and performing limited accumulation

procedures is also available upon receipt of a stamped self-addressed envelope, and a blank,

formatted diskette in the appropriate formats (3% for MAC/OS; 5% for

MS-DOS).

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The Efficacy of Rational-Emotive Therapy 359

3. The study used a quantitative statistic that could be converted to an effect-

size estimate.

4. The study gave the number of subjects in each treatment or control group.

Studies were rejected because of uninterpretable statistics, or because insuffi-

cient information regarding treatments or experimental procedures were pre-

sented. Single-subject designs and case studies were also excluded. With these

criteria and exclusions, 7 studies were found, yielding 236 comparisons between

RET and a baseline measure, a control group, or other form of therapy.

Effect Size

Estimation

Each comparison of RET to a baseline measure, a control group, or a treatment

group was expressed in terms of the standardized difference between mean scores,

d (Cohen, 1977).

Because of limitations in the data reported it was not always possible to calculate

d directly. In some of these cases it was possible to calculate d from t, F, r or a

probability value. In others, where a two-way ANOVA was used, the F was first

converted to ETA using an algorithm presented by Haase (1983), and then to d.

When the study merely stated that a significant difference was found, the

probability was set at

.05 and d was calculated using conversion algorithms.

Procedures for these indirect calculations of d are described by Cohen (1977);

Hunter, Schmidt, and Jackson (1982); Smith, Glass, and Miller (1980); and Wolf

(1986).

The majority of the studies used more than one outcome measure. To avoid

biasing the data, the present study averaged the effect-sizes in multiple outcome

studies to produce a single statistic, thereby preserving the independence of each

comparison. For a discussion of the issue of averaging multiple outcome results,

see Hunter et al. (1982) or Wolf (1986).

Coding Procedures

After converting the study statistics to effect-sizes, study characteristics were

examined and coded using a 28-variable coding scheme (see footnote 1). These

coding variables included the year of the comparison (either publication or

acceptance date), level of therapist training, and client or subject problem diagno-

sis, based on a coding procedure originally presented by Smith et al. (1980).

1. Neurotic: subjects had problems such as the following: personal growth

problems, achievement problems, social anxiety, excessive anger, lack of

assertion, depression, behavior problems, speech anxiety, potential for drop-

ping out of school.

2. Phobic: subjects were diagnosed as suffering from some form of phobia,

including simple and complex phobias.

3.

Normal:

subjects had no immediately discernible problem.

4. EmotionallSomatic: subjects suffered from either asthma, sexual dysfunction,

insomnia, obesity, migraine headaches,

chronic heart disease, or were on

home dialysis.

5. UnknownlUnclassified: subjects could not be classified into any of the previous

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360

L.. C. Lyons and P. J. Woods

categories. (This category also included those problems where the incidence

was too small to merit a separate classification group.)

Comparison groups were coded according to conditions or therapies as follows:

1. Baselive: pretreatment measure taken at the start of therapy.

2. ,Vo

Treatment Corltrol

(NTC): not receiving therapeutic intervention.

3.

Waiting List Control

(MLC): not receiving therapy but given the expectation of

being on a waiting list for treatment.

4.

Attention ControllPlacebo

(ACP): a placebo treatment given.

5.

Cognitiw Behavior Modification

(CBM): given therapy using the techniques and

theories of behavior and personality change based on Bandura (1977),

Meichenbaum (1977), Mahoney (1974), and others.

6.

Behazlior Therapy:

given therapy using principles and procedures based on

Learning Theory, including treatments based on systematic desensitization,

exposure techniques,

behavior modification, and other conditioning-based

procedures.

7. Otheriljnclassified: given other therapies including psychodynamic, Gestalt,

humanistic, Adlerian, Reality Therapy, vocational/personal development coun-

seling, and undifferentiated counseling. This category also included those

therapies whose numbers did not merit a separate category.

To determine whether the effectiveness of RET was a function of the degree of

similarity to strict Rational-Emotive Therapy, two separate coding schemes were

used. First, RET studies were classified into comparisons using strict RET meth-

ods; Systematic Rational Restructuring, or other similar therapy; or CBM treat-

ment procedures, which relied on many RET techniques. Second, a rating scheme

was derived to assess the degree of similarity of the treatment groups therapy to

RET. This rating scheme was a six-point Likert scale from 0 (no elements of RET)

to 5 (all elements of RET). The studies were rated on various salient features of

RET, such as identification, disputation, and modification/replacement of irratio-

nal beliefs, homework assignments, and collaborative empiricism between thera-

pist and client, etc. Both the treatment and comparison groups were coded in this

manner.

Subject and therapist assignment to treatment and comparison groups were also

coded. For the subjects, the categories included:

1.

Random assignment:

participants assigned randomly to treatment and compar-

ison groups;

2. Matching: participants matched between groups;

3.

honrandom assignment: ex-post facto

matching, covariance adjustments, or

equating on pretest scores, or where participants were assigned to groups

based on the order of their appearance at the clinic or studys facility; and

4.

Unknown:

the method of subject assignment was not mentioned.

Therapist assignment used the same coding procedure with the additional

category of Single Therapist.

Subject recruitment was also coded, using procedures adapted from Smith et al.

(1980). The participants were classified according to the following:

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The Efficacy of Rational-Emotive Therapy

?6

1.

2.

3.

4.

5.

A

sought help on their own;

responded to an advertisement;

were directly solicited by the therapist, typically by offering treatment to

psychology students with extreme scores on a criterion measure;

were referred for treatment by a third party; or

were committed for therapy with no choice, as in court-ordered treatments.

rating scheme was developed to assess the effect of variations in internal

validity on effect-size, and was as follows:

1. High validity: random assignment for subjects and therapists, a low estimated

attrition rate (5 IS%), and used outcome measures deemed low in reactivity;

2.

Medium internal validity:

random assignment, or matching for participants and

therapists, but did not mention, or had a high estimated attrition rate

(>lS%), and used outcome measures rated medium or low in reactivity;

3. Low internal validity: nonrandom assignment (other than matching), a high

estimated attrition rate, (or did not mention attrition), and medium or highly

reactive outcome measures.

To assess outcome measure characteristics of the sample, two coding schemes

were used according to the type of test used for assessment. Coded outcome

measures included:

1.

2.

3.

4.

fear and anxiety measures, such as Behavioral Approach Tests, and anxiety

questionnaires;

standardized tests and measures in common use, such as the Irrational

Beliefs Test (Jones, 1968), and the Beck Depression Inventory (Beck, 1978);

physiological measures, such as the electrodermal response, heart rate, and

EEG;

unclassified, including those measures which could not be assigned to any of

the previous categories, or there were not enough comparisons to merit a

separate classification.

TABLE

1 Demographic Characteristics

of the Sample

Variable

M

SD

Range

rd

Number of therapists 2.3

1.8 1-8 - ,025

Therapist training 5.2

0.6 4-6 .296**

Number of subjects 26.7

18.8 5-115

-.221*

Age 25

11.3 9-70 ,052

% male subjects 42.4 20.4 O-100 .091

Therapist training ratings: 4 = MA degree, 5 = PhD

candidate or psychiatry resident, 6 = PhD therapist or

psychiatrist with at least 1 year experience beyond the

granting of a degree.

*p

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362

L. C. Lyons and P. J. Woods

TABLE 2. Type of Subjects in RET

Outcome Studies

Subject Category IV,,

Z of Sample

d

SC,

Students

142

60.2 ,914 ,917

Therapy

clients 94

39.8 1.002 ,959

Number of effect-sizes.

Test reactivity refers to the degree of similarity between the treatment and the

test measures. The reactivity of the outcome measures was assessed using a rating

scheme adapted from Smith et al. (1980).

High reactive measures revealed or had a direct and obvious relationship

with the treatment. This category also included nonblind symptom ratings by

the therapist, behavioral approach tests assessed by the experimenter and, in

the case of RET-oriented treatments, irrational beliefs tests.

Medium reactive measures were defined as standard tests and measures with

a minimal connection to the therapy. Examples included the MMPI, Beck

Depression Inventory and the State-Trait Anxiety Inventory (Spielberger,

Gorsuch, & Lushene, 1970) for therapies not explicitly treating depression or

anxiety.

Low reactive measures included those tests and measures not easily influ-

enced by the parties involved. These measures did not have an immediately

discernable relationship with the treatments being assessed. Examples in-

cluded the electrodermal response and other physiological measures, grade-

point average, blind ratings and decisions, and blind discharge from hospital.

RESULTS

Table I presents several demographic characteristics of the studies examined in

the present quantitative review.

Year of publicatio1~ ranged from 1970 to 1988,

with a median of 1978.5. Publication year was not related to effect size. The

median training level for the therapists was five years (PhD candidate or psychi-

atric resident). Therapist training was significantly related to effect-size. The

number of subjects per comparison was also significantly related to effect size:

smaller numbers of participants in each comparison group was related to larger

TABLE 3. Subject Diagnosis

l\, *

cs

a f Sample

d

SC,

Neurotic**

105

44.5 .989 1.022

Phobic

85

36.0 .821 .725

Normal 21 8.9 .523h .287

Emotional/somatic

16

6.8 1.924 1.260

Unclassified

9

3.x C453 ,836

*Number of Effect-sizes.

**Effect-sizes with different superscript letters are signifi-

cantly different at the p

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The Effi cacy of Rati onal-Emot iv e Therapr

363

TABLE 4. Other Treatment

Characteristics

Variable

M S

Range rd

Experimental group

4.16 .99 l-5 .097

similarity to RET rating

Comparison group

0.20 .74 O-5.0 -.152*

similarity to RET rating

Duration of therapy

10.2 9.0

I-45.0

.299t

(in hours)

Duration of therapy

6.2 4.1 1-18.5 .172**

(in weeks)

*p

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364

L c. Lyl~ls

nrcd

P. J.

12ood.s

TABLE 6. Treatment Mode

Individual

29 12.3

1.102

,826

GroLlp

207 87.7

.927

,947

Number of effect-sizes.

RET

for the comparison groups. Duration of therapy was found to be significantly

related to effect-size.

Table 5 presents the effect-size estimates broken down bv comparison groups.

To facilitate the analysis and understanding of these results a Binomial Effect-Size

Display (BESD: Rosenthal & Ruben, 1982) was also employed.

The BESD displays the change in improvement rate (or success rate, survival

rate, etc.) attributable to a certain treatment intervention. In other words, the

BESD is the estimated difference in the probabilities of improvement between

the

treatment and control, or between pre- and postint.er-vention. It is defined as

BESD = j.50 - r/Z) to (.50 + r/Z), where r is a point biserial correlation. For

example, an effect-size of d = .872 (r = .40), when expressed as a BESD, shows

that the improvement

or improvement rate prior to intervention is 3Oci;, while

after the intervention the improvement rate increases to 707~.

The overall effect-size was .949. In terms of collapsing across all comparisons,

using the BESD, 27.2?

c of the sample would have demonstrated significant

improvement without KET intervention.

fn contrast,

72.5 of

the sample who

received RET demonstrated significant clinical improvement over those partici-

pants not receiving RET.

TABLE 7. Subject and Therapist Assignment to

Treatment and Control Groups

Assignment

Category

Random

Matching

~onrandnm

Unknown

Subject Assignment

7r of

lu,,-

Sample

189

80.1

19

8.1

17

7.2

11

4.7

d

S

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The Efficacy of Rational-Emotive Therapy

TABLE 8.

Subject Solicitation

365

Solicitation Category

N,S*

7c of Sample d

Xl

Sought help** 26 11.0 .859 ,835

Advertisement

response

89 37.7 .987 ,931

Solicited by

E

72 30.5 .76&Y ,695

Third-party referral 26 11.0 1.486 1.446

Committed to therapy 18 7.6 .894 ,843

Missing Data/No Information 5 2.1 - -

*Number of effect-sizes.

**Effect-sizes with different superscript letters are significantly different at

the pc.05 level using Duncans Multiple Range Test.

In comparing RET to all other treatment conditions, a one-way ANOVA

indicated significant differences in effect-sizes among the various comparisons (F

(6,229) = 9.617, p < .OOl). A Duncans Multiple Range Test indicated that, except

for those comparisons with a waiting list control group, comparisons of RET

against baseline conditions had significantly higher effect-sizes than all other

comparison groups. Compared to baseline, the mean effect-size was 1.371. Using

the BESD indicator, the pretherapy clinical improvement rate was 21.5%. Follow-

ing RET intervention, the improvement rate was

78.5 .

Comparisons with therapies using CBM or Behavior Therapy demonstrated the

lowest mean effect-sizes of the sample. A Duncans Multiple Range Test indicated

that CBM and Behavior Therapy had significantly lower effect-sizes than any of

the other treatment conditions.

Table 6 shows the mean effect-sizes for individual and group therapy formats.

No significant differences were found between comparisons using an individual or

a group therapy format (t (234) = 0.946, ns).

Tables

7, 8,

and 9 present the analyses of the methodological characteristics of

the sample. Table 7 presents the subject and therapist assignments to treatment

and comparison groups. No significant differences were found among any of the

subject (F (3,232) = 0.573, ns) or therapist assignment categories (F (4,231) =

1.807, ns).

Table 8 presents the subject solicitation data.

Significant differences among

solicitation categories were found (F (4,226) = 3.020, p = < .02). Participants

referred by a third party had significantly higher effect-sizes than any other

TABLE 9. Internal Validity Rating

Validity Rating

N,S*

% of Sample

d

s,

Low** 31 13.1 .81 lab .670

Medium 108 45.8 ,818 ,778

High 97 41.1 1.138b 1.119

*Number of effect-sizes.

**Effect-sizes with different superscript letters are signifi-

cantly different at the pc.05 level using Duncans Multiple

Range Test.

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366

L. C. Lyons and P. J. Woods

TABLE 10. Type of Outcome Measures

Outcome Measure

N,,* % of Sample

d

Fear/anxiety** 144 61.0 ,767 ,740

Standard text measures 67 28.4 .813 612

Physiological measures 6 2.5 3.883h ,494

Unclassified 19 8.1 1.877 1.207

*Number of effect-sizes.

**Effect-sizes with different superscript letters are signifi-

cantly different at the $1~.05 level using Duncans Multiple

Range Test.

solicitation category. No other differences were found to be significant.

Table 9 presents the internal validity rating of the sample (with high internal

validity defined by random assignment, low attrition rate, and outcome measures

which did not have an immediately discernible relationship with the treatments

being assessed) and the associated effect sizes. Significant differences were found

among the internal validity categories (F (2,233) = 3.472, p = < .05). A Duncans

Multiple Range Test indicated that comparisons with high internal validity rating

had significantly higher effect-sizes than comparisons with medium internal

validity ratings. No other comparison was found to be significant.

Table 10 presents the breakdown of effect-sizes by the type of outcome

measure. Significant differences were found among the effect-sizes associated with

different outcome measures (F (3,232) = 43.873, p = < ,001). Physiological

measures had significantly higher effect-sizes than all other outcome measures.

The Unclassified category had a significantly greater mean effect-size than either

Fear/Anxiety, or Standard Test Measures. Fear/Anxiety and Standard Test Mea-

sures were not significantly different from each other.

Table 11 presents the breakdown of effect-sizes by the reactivity of the outcome

measure (where low reactivity means the outcome measures did not have an

immediately discernible relationship with the treatments being assessed). Signifi-

cant differences were found among reactivity ratings

(F

(2,233) = 14.886, p = -=c

.OOl). A Duncans Multiple Range Test indicated that outcome measures rated low

TABLE 11. Reactivity of the

Outcome Measures

Reactivity Rating

NeS*

of

Sample

d

S,

Low 36 15.3 1.686

1.492

Medium 125

53.0 .802b

.700

High

75

31.8 .83gb

.759

*Number of effect-sizes.

**Effect-sizes with different superscript letters are signifl-

cantly different at the PC.05 level using Duncans Multiple

Range Test.

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The Efficacy of Rational-Emotive Therapy 367

in reactivity had significantly higher effect-sizes than measures rated medium or

high in reactivity.

DISCUSSION

The results demonstrated that RET is an effective form of therapy. The efficacy

was most clearly demonstrated when RET was compared to baseline and other

forms of controls. The differences among comparisons of RET to CBM and

Behavior Therapy were not significant.

One general criticism of RET outcome studies has been the great number of

analogue studies. Ledwidge (1978) and Zettle and Hayes (1980) claimed that by

using student volunteers, the therapeutic efficacy of RET was not demonstrated.

Based on the present results, this criticism is not warranted. No significant

differences were found between comparisons of student and clinical subjects. Most

of the studies involving students were investigating genuine problems. While these

problems may not be as severe as those seen in clinical settings, if RET was not an

effective form of therapy, or was not effective for more severe problems, a

disparity between results found with students and psychotherapy clients would

have been found.

Reviews with a definitive allegiance to RET (e.g., DiGuiseppe & Miller, 1977)

criticized many RET outcome studies for using postgraduate students as thera-

pists. This clearly remains a problem. The majority of therapists in the studies

reviewed were PhD candidates, with relatively little experience compared to

professional therapists. The results suggest that therapist experience is an impor-

tant variable in influencing the effectiveness of RET.

These results with therapist experience vary somewhat from Miller and Berman

(1983). In their quantitative review of CBM studies, therapist experience was not

related to effect size. One explanation of this difference lies in how Miller and

Berman (1983) assessed therapist experience, measured in years. In contrast, a

rating scheme was used in the present study because information regarding exact

clinical experience was generally not available. If more detailed information had

been readily available, results similar to the Miller and Berman (1983) may have

been found.

Given this difference with previous results, the findings of the present quanti-

tative review indicate that the more experienced the therapist, the more effective

the treatment. There is, however, one qualification of this statement; there is no

real guarantee that the therapy being used was actually RET as practiced and

taught by the Institute of Rational-Emotive Therapy. As Wessler (1983) noted, it

is very possible that procedures thought to be RET may not have been strict RET,

but rather methods subject to experimenter interpretation. An attempt was made

to control for this factor by using RET similarity ratings of both the treatment and

comparison therapies. No relationship between effect-size and the number of RET

principles actively used during the treatment was found. Thus, the true relation-

ship between similarity of the treatment to RET may be somewhat obscure. One

recommendation is that researchers publish more detailed descriptions of their

procedures or, at least make available to reviewers, detailed treatment manuals.

This allows a reviewer to determine whether the procedures involved were actually

elegant or inelegant RET (Ellis, 1980).

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368 L. C. Lyons and P. J. Woods

One of the criticisms made by DiGiuseppe and Miller (1977), and McGovern

and Silverman (1984) was that the short duration of the treatments may limit the

effectiveness of RET. The results confirm this criticism. Larger effect-sizes were

related to therapy duration. The longer the therapy, the larger the effect-size.

However, the magnitude of the correlations was not very large, accounting for

only 8.9% of the variance in effect-sizes for duration in hours, and 35% of the

effect-size variance for duration in weeks. Given this limitation, there Zs a relation-

ship between duration and therapy effectiveness. This is clearly demonstrated with

those studies which used only one or two treatment sessions - these studies had

the lowest effect-sizes.

This study attempted to examine methodological criticisms in several ways. First,

an attempt was made to relate effect-size to attrition or dropout rates. However, no

detailed analysis of the attrition rates was possible since only nine of the studies

reported any attrition rates, thereby biasing the results of the present quantitative

review. It is obviously not defensible to assume that all 61 of the studies that did

not report on attrition had zero dropout rates. Therefore, the conclusion that

RET is an effective form of therapy must be tempered with the consideration that

this conclusion is only tenable for those individuals who manage to complete

therapy.

Next, it is of interest to note that those studies judged high in internal validity

also tended to have high effect-sizes. The obvious implication is that well-

conducted studies comparing the effectiveness of RET to other treatment modes

most clearly demonstrate the effectiveness of RET procedures.

Another methodological factor that was neglected by many studies was the

follow-up status. But the majority of studies (81.4%)) did not report on follow-up

data and, therefore, any determination of the long-term effectiveness of RET

could not be made.

Contrary to what was expected, the reactivity of the outcome measures indicated

that larger effect-sizes were associated with measures low in reactivity. These

results are different from Dush, Hirt, and Schroeder (1983). They examined this

variable in the context of a meta-analysis of studies that used some form of

self-statement modification. These results are also different to what was found by

Smith et al. (1980). Both of these studies found positive relationships between test

reactivity and effect-size. One explanation of the differences is that while RET

studies used reactive measures of irrational beliefs, they also included less reactive

measures of adjustment, such as locus of control and anxiety measures. The net

outcome was that the average reactivity for the present analysis was lower than in

the previously mentioned quantitative reviews.

Given the previously mentioned limitations to the present quantitative review,

these results suggest that RET is an effective form of therapy. Compared to

baseline assessments and control groups, those individuals receiving RET demon-

strated significant improvement.

These results do not support the Zettle and

Hayes (1980) conclusion that there is little evidence for the clinical efficacy of

RET. In contrast, RET was shown to be an effective form of therapy. Perhaps it is

time to stop the needless and inefficient discussion of the efficacy of this therapy.

Rather, a better focus of investigations and reviews would be to determine which

factors, or combinations thereof, contribute most to the effectiveness of RET.

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The Efficacy of Rational Emotive Therapr 369

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Cohen, J. (1977). Statistzcal power analysti for the behavi oral sciences. New York: Academic Press.

DiGiuseppe, R. A., & Miller, N. J. (1977). A review of outcome studies on Rational-Emotive Therapy.

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Progress in Behavi or M odi fi cati on, 9, 125-166.

Received May 14 1990

Accepted July 27 1990