Results

The data were analyzed to address five core questions related to the impact of JSTOR: (1) how faculty searched for information; (2) which faculty used JSTOR; (3) how journals were used; (4) how the Internet was used; and (5) how journal use and Internet use correlated with JSTOR use.

Information Searching

Table 11.1 summarizes data on how faculty searched for information. The proportion of faculty using the search strategies did not differ significantly by institution or discipline, with the exception of three strategies. First, the proportion of Michigan economists who reported browsing library shelves (46%) was significantly less than the proportion of five-college historians who used this strategy (86%). Second, the proportion of Michigan economists who reported searching card catalogs (14%) was significantly less than the proportion of five-college historians who used this strategy (39%). And finally, the proportion of Michigan economists who reported browsing departmental collections (48%) was significantly greater than the proportion of five-college historians who used this strategy (4%).^[1]

Who Used JSTOR

Overall, 67% of the faculty did not use JSTOR,^[2] 14% used JSTOR once a year, 11% used JSTOR once a month, and 8% used JSTOR once a week. None of the faculty used JSTOR daily. Table 11.2 summarizes JSTOR frequency of use by type of institution and discipline. A comparison of use by type of institution shows a higher proportion of JSTOR users at the five colleges (42%) than at the University of Michigan (27%). A further breakdown by discipline shows that the five college economists had the highest proportion of users (46%), followed by the Michigan economists (40%), the five-college historians (39%), and the Michigan historians (16%). One way to put JSTOR use into perspective is to compare this activity with similar, more familiar on-line activities, such as literature searching. Overall, 21% of the faculty did not do on-line searches, 25% searched once a year, 25% searched once a month, 25% searched once a week, and 4% searched daily. Table 11.3 summarizes data on the frequency of on-line searching by type of institution and discipline for the same faculty described in Table 11.2. A comparison of on-line searching by type of institution shows a higher proportion of on-line searchers at the five colleges (85%) than at the University of Michigan (76%). A further breakdown by discipline shows that the five-college economists had the highest proportion of searchers (89%), followed by the five-college historians (82%), and the Michigan economists and historians (both 76%).

Figure 11.1 shows a plot of the cumulative percentage of faculty per institution who used JSTOR and who did on-line searches versus the frequency of these activities. For example, looking at the values plotted on the y-axis against the "Monthly" category shows that over three times as many Michigan faculty searched once a month or more (51%) compared with those who used JSTOR at least once a month (15%). Similarly, over two times as many of the five-college faculty searched once a month or more (62%) compared with those who used JSTOR at least once a month (25%). A further breakdown by discipline shows that

over twice as many of the five-college economists searched once a month or more (73%) than used JSTOR at least once a month (31%), that over six times as many of the Michigan historians searched once a month or more (54%) than used JSTOR at least once a month (8%), that over twice as many of the five-college historians searched once a month or more (50%) than used JSTOR at least once a month (21%), and that over twice as many of the Michigan economists searched once a month or more (48%) than used JSTOR at least once a month (23%).

Journal Use

Table 11.4 summarizes how faculty used features of journals. Across all journal features, patterns of use were similar except in two areas. First, the proportion of Michigan historians who used article abstracts (31%) was significantly smaller than the proportion of Michigan economists (81%), five-college economists (89%), and five-college historians (61%) who used abstracts. Second, the proportion of Michigan economists who used book reviews (49%) was significantly smaller than the proportion of five-college historians (100%), Michigan historians (98%), and five college economists (85%) who used book reviews.

Overall, faculty in the sample reported that they regularly used 8.7 journals, that they subscribed to 4.1 of these journals, and that 2.2 of these journals were also in JSTOR. Table 11.5 summarizes journal use by institution and discipline. There were no significant differences in the number of journals used across institution and discipline, although Michigan historians reported using the most journals (8.9). There were also no significant differences across institution and discipline in the number of paid journal subscriptions among the journals used, although again Michigan historians reported having the most paid subscriptions (4.6). There was a significant difference in the number of journals used regularly by the economists that were also titles in JSTOR (M = 2.9) compared with those used by the historians ([M = 1.7], t [158] = 5.71, p < .01).

[Full Size]

Figure 11.1.
Cumulative percentage of on-line searchers versus JSTOR users, by frequency of use
and type of institution (n = 147)

Further examination of differences in use of journals shows a much greater consensus among the economists about the importance of the economics journals in JSTOR than among the historians about the history journals in JSTOR. For example, Table 11.6 shows the economists' ranking in order of use of the five economics journals chosen for JSTOR. The American Economic Review was cited among the top ten most frequently used journals by over 75% of both the Michigan and the five-college economists; the Journal of Political Economy was cited

among the top ten by over 60% of both the Michigan and the five-college economists; and the Quarterly Journal of Economics and the Review of Economics and Statistics were cited among the top ten by over 50% of the Michigan economists and by over 40% of the five-college economists. By contrast, Table 11.7 shows the historians' ranking in order of use of the five history journals chosen for JSTOR. The American Historical Review was cited among the top ten most frequently used journals by over 60% of both the Michigan and the five-college historians. However, none of the other four journals were used by a majority of the historians at Michigan or at the five colleges.

Internet Use

Overall, faculty reported weekly use of e-mail (M = 4.3), monthly use of on-line catalogs (M = 3.2) and the Web (M = 3.0), and two or three uses per year of FTP (M = 2.3) and on-line database (M = 2.1). Table 11.8 summarizes the use of these Internet applications by institution and discipline. In terms of e-mail use, Michigan historians (M = 3.3) were significantly lower than the Michigan economists (M = 4.9), the five-college economists (M = 5.0), and the five-college historians (M = 4.7). In terms of World Wide Web use, Michigan historians (M = 1.8) were significantly lower than everyone, while the five-college historians (M = 2.9) were significantly lower than the five-college economists (M = 4.2) and the Michigan economists (M = 3.9). In terms of FTP use, the Michigan historians (M = 1.4) and the five-college historians (M = 1.7) differed significantly from the Michigan economists (M = 3.4) and the five-college economists (M = 2.7). In terms of on-line database use, the Michigan historians (M = 1.6) were significantly lower than the five-college economists (M = 2.9). Faculty did not differ significantly in terms of on-line catalog use.

The Relationship of Journal and Internet Use to JSTOR Use

Examination of the frequency of JSTOR use among faculty aware of JSTOR (n = 78) showed that 58% of the respondents had varying levels of use, while 42% reported no use. Using the frequency of JSTOR use as the dependent variable, the faculty who reported no use were censored on the dependent variable. The standard zero, lower-bound tobit model was designed for this circumstance (Tobin 1958). Most important, by adjusting for censoring, the tobit model allows inclusion of negative cases in the analysis of variation in frequency of use among positive cases, which greatly enhances degrees of freedom. Therefore, hierarchical tobit regression analyses were used to examine the influence of demographic characteristics, journal use, search preferences, Internet use, and attitude toward computing on the frequency of JSTOR use. Independent variables used in these analyses were selected on the basis of significance in univariate tobit regressions

on the frequency of use variable. Table 11.9 summarizes the independent variables used in the multiple tobit regression analyses.

Table 11.10 summarizes the results of the hierarchical tobit regression of demographic, journal use, search preference, Internet use, and computing attitude variables on frequency of JSTOR use. The line second from the bottom in Table 11.10 summarizes the log likelihood score for each model. Analysis of the change in log likelihood score between adjacent models gives a measure of the significance of independent variables added to the model. For example, in Model 1, the addition of the demographic variables failed to produce a significant change in the log likelihood score compared to the null model. By contrast, in Model 2, the addition of journal use variables produced a significant change in the log likelihood score compared to Model 1-suggesting that the addition of the journal

use variables improved the fit in Model 2 over Model 1. Similarly, the addition of search variables in Model 3 and of Internet use variables in Model 4 both produced significant improvements in fit, but the addition of the computer attitude variable in Model 5 did not. Therefore, Model 4 was selected as the best model. From Model 4, the coefficients for gender, article copying, abstract reading, and searching on-line catalogs are all positive and significant. These results suggest that, controlling for other factors, men were 0.77 points higher on frequency of JSTOR use than were women, that there was a 0.29-point increase in the frequency of JSTOR use for every point increase in the frequency of article copying, that faculty who read article abstracts were 0.82 points higher on frequency of JSTOR use than were faculty who didn't read abstracts, and that there was a 1.13point increase in the frequency of JSTOR use for every point increase in the frequency of on-line catalog searching. From Model 4, the coefficients for affiliation with an economics department and the number of paid journal subscriptions are both negative and significant. These results suggest that, controlling for other factors, economists were 0.88 points lower on frequency of JSTOR use than were historians and that there was a 0.18-point decrease in frequency of JSTOR use for every unit increase in the number of paid journal subscriptions.