never be fully offset by their enthusiasm and
“authenticity.”
A contribution of major proportions was
Rogers’emphasis on research. He was responsible
for the first concerted efforts to carry out research
on the therapeutic process. It was he who first
employed recordings of therapy sessions to study
the process and to investigate its effectiveness. The
use of recordings is now a staple ingredient of train-
ing and research. Prior to Rogers, the sanctity of
the therapy room was guarded with a vengeance.
Rogers opened up therapy and made it an object of
study rather than a subject of mystery. In making
available recordings and transcripts of his own ther-
apy sessions, he exhibited a degree of courage
unusual for its time (though it may be common-
place today).
In addition to the pioneering efforts of Rogers
and others in the recording and transcription of
interviews, significant efforts were made to investi-
gate the outcomes of therapy. For example, Rogers
and his colleagues developed indices of therapeutic
outcome based on client ratings of their present and
their ideal self-concept, along with various indica-
tors of improvement gleaned from counseling
sessions, such as the ratio of client-to-therapist talk
and the responsibility for talk (e.g., Cartwright,
1956; Rogers & Dymond, 1954; Rogers, Gendlin,
Kiesler, & Truax, 1967; W. U. Snyder, 1961;
Truax & Carkhuff, 1967; Truax & Mitchell, 1971).
As noted in Chapter 11, meta-analyses of stud-
ies including a client-centered treatment condition
have indicated an effect size of .62, indicating that
an adult client who received this form of therapy
was functioning (on average) better than 73% of
those who did not receive treatment. To investigate
whether this finding characterized“newer”research
on client-centered therapy, two additional meta-
analyses have been conducted.
Greenberg et al. (1994) conducted a meta-analysis
of studies published between 1978 and 1992. It is note-
worthy that the authors could identify only eight
studies conducted during this time period that investi-
gated the efficacy of client-centered therapy and also
included a control group. The average effect size across
these studies was .88; on average, an adult client in
these studies was functioning better than 81%
of those not receiving treatment. Greenberg and
colleagues were also able to evaluate the relative effec-
tiveness of client-centered therapy compared to other
forms of psychological treatment. Of the seven rele-
vant comparisons, in only one instance did client-
centered therapy outperform another treatment (in
this case, short-term dynamic therapy; Meyer, 1981).
Elliott and colleagues (2004) presented results
of a meta-analysis of studies published since 1992.
They located 11 studies of the efficacy of client-
centered therapy (in which a control group was
also evaluated) and reported a mean effect size of
.78. Compared to other forms of treatment, across
28 studies, client-centered therapy (on average) was
no more effective than other treatments.
Most recently, Elliott and Freire (2010)
reported on a meta-analysis of almost 200 studies of
Person-Centered/Experiential therapies. Across
studies, they found that the average adult client
receiving this form of therapy reported significant
positive change from pre- to posttreatment, and
these treatment gains seemed to be maintained for
at least one year, on average. Compared to clients
that received no therapy, clients that received
this form of treatment showed significant improve-
ment (an average effect size of .78). Finally, across
those studies that compared Person-Centered/
Experiential therapies to other forms of psycholog-
ical treatment (n 109 studies), no significant
differences in outcome were found, suggesting
equivalent effects.
What aspects of person-centered/experiential
therapies seem most helpful to clients? A recent series
of meta-analyses sought to identify aspects of treat-
ment often associated with this approach that are
significantly related to outcome. It is important to
note, however, that these meta-analyses did not
restrict the selection of studies to only those that used
Person-Centered/Experiential therapies. Rather,
psychotherapy studies were selected for these meta-
analyses based on their measurement of the con-
structs that were targeted. As mentioned earlier, the
therapeutic alliance is believed to be an important
correlate of outcome and is often considered a com-
mon factor that is responsible for the effects ofPSYCHOTHERAPY: PHENOMENOLOGICAL AND HUMANISTIC-EXISTENTIAL PERSPECTIVES 379