 2. History, Measurement, and Conceptual Elaboration of the Big‑Five Trait Taxonomy  53
in the questionnaire tradition. Goldberg’s 
(1992) 100-item TDA and its abbreviated 
40-item version (Saucier, 1994b) is the most 
commonly used measure consisting of single 
adjectives. The BFI has been used in several 
thousand research studies, where subject 
time is at a premium and its short-  phrase 
item format provides more context than 
Goldberg’s single-  adjective items but less 
complexity than the sentence format used by 
the NEO questionnaires; the BFI items are 
also somewhat easier to understand (Benet- 
Martinez & John, 1998).
How well do these different Big Five mea -
sures converge? A number of researchers 
have reported on the psychometric charac -
teristics of these instruments, and a few have 
compared two of them with each other (e.g., 
Benet-  Martinez & John, 1998; DeYoung, 
2006; Goldberg, 1992; McCrae & Costa, 
1987). Besides the John and Srivastava 
(1999) study, however, no published studies 
have compared all three. To provide such a 
comparison, we summarize findings from 
a large dataset of self-  reports on all three 
measures. The sample consisted of 438 un -
dergraduates at the University of California, 
Berkeley (see Soto & John, 2017a; Soto & 
John, 2008) who completed the BFI-2, the 
BFAS, Saucier’s (1994b) 40-item version of 
Goldberg’s (1992) TDA, as well as Costa 
and McCrae’s (1992) NEO-PI-R, from 
which we scored both the 30 facets and the 
NEO-FFI domain scores. The data thus rep -
resent a multitrait–  multimethod (MTMM) 
design in which the methods are the three 
Big Five self-  report instruments (see John & 
Benet-  Martinez, 2000).
Reliability of  the Three  Instruments
Overall, the coefficient alpha reliabilities, 
shown in Table 2.5, were impressive for 
these relatively short scales, and relatively 
similar in size across instruments; the mean 
of the alphas was .84 for the TDA scales, 
.86 for the BFI-2, and .81 for the NEO-FFI, 
which had the longest scales (12 items for the 
NEO-FFI and BFI-2, compared to eight for 
the TDA). Across instruments, Extraversion, 
Neuroticism, and Conscientiousness were 
measured most reliably (all clearly above 
.80 on all instruments), whereas Agreeable -
ness and Openness tended to be somewhat less reliable. The scales with the lowest re -
liabilities were the NEO-FFI Openness and 
Agreeableness scales, similar to the values 
reported in the NEO-PI-R manuals and 
also replicating two other college samples 
(e.g., Benet-  Martinez & John, 1998). John 
and Srivastava (1999) noted that several 
NEO-FFI Openness items in their data did 
not correlate well with the total scale, and 
these less reliable items came from particu -
lar openness facets, namely from openness 
to action (e.g., trying new and foreign foods) 
and from openness to values (e.g., looking to 
religious authorities for decisions on moral 
issues, reverse-  scored).
Convergent Validity 
across  the Three  Instruments
Overall, we expected the convergent validi -
ties across the three instruments to be sub -
stantial. However, we had already noted 
some potential differences in the way the 
three instruments define Extraversion and 
Openness. The NEO Extraversion do -
main had already been defined in terms of 
six facets before Costa and McCrae added 
domain scales for Agreeableness and Con -
scientiousness in 1985 and facet scales for 
these two factors in 1992. Thus, the warmth 
facet scale, included in the NEO-PI-R Ex -
traversion domain, also correlates sub -
stantially with their Agreeableness domain 
scale (Costa & McCrae, 1992). In contrast, 
Goldberg (1992), John (1990), and Saucier 
and Ostendorf (1999, Tables 4.3 and 4.4) 
all found in independent analyses that trait 
adjectives related to warmth correlate more 
highly with Agreeableness than with Extra -
version. Thus, John and Srivastava (1999) 
found that the NEO-FFI Extraversion scale 
showed much less convergence with either 
TDA or the BFI than those two instruments 
with each other.
The other potential difference involves 
the fifth factor. As described earlier, Gold -
berg (1992) prefers to interpret this factor 
as intellect or imagination (Saucier, 1992). 
Similarly, the BFI-2 Openness scale does not 
include items conceptually related to Costa 
and McCrae’s (1992) values and actions fac -
ets, because preliminary BFI items based on 
prototype items related to conventionality 
(i.e., relevant to the NEO-PI-R values facet) 