M. Chandrashekaran et Rk. Sinha, ISOLATING THE DETERMINANTS OF INNOVATIVENESS - A SPLIT-POPULATION TOBIT (SPOT) DURATION MODEL OF TIMING AND VOLUME OF FIRST AND REPEAT PURCHASE, Journal of marketing research, 32(4), 1995, pp. 444-456
The authors present the Split-Population Tobit (SPOT) duration model t
o incorporate two conceptually distinct dimensions of innovativeness i
n a single framework, namely, the timing and volume of adoption. Rathe
r than utilizing a diffusion model specification based on word-of-mout
h and social contagion effects, the present approach uses a growth mod
el specification and delineates a general function of time to describe
the distribution of adoption timing. Estimation and several validatio
n exercises performed on a data set describing the diffusion of person
al computers across a sample of over 3000 U.S. firms provide strong su
pport for the superiority of the SPOT model over models derived from r
estricted conceptualizations of innovativeness. The empirical work, al
beit modest, tests the impact of covariates, such as firm-size and dec
ision-centralization, on the dimensions of innovativeness and sheds li
ght on some inconsistent findings in the innovation adoption literatur
e. The authors subsequently derive the extended SPOT model (EXT-SPOT)
to incorporate repeat purchase volume and timing in the SPOT framework
, Finally, they discuss limitations, further research directions, and
implications for the practitioner.