Geography Reference
In-Depth Information
Table 17
.
6
Scientist mobility: mean degree (within and between blocks)
Within
Between
Between
Within
P1
Exit
Exit and
permanent
Permanent
and exit
Permanent
N
107
107
32
32
Mean degree
0.561
0.514
1.719
0.938
Standard deviation
(1.361)
(0.883)
(2.976)
(1.900)
P2
Entry
Entry and
permanent
Permanent
and entry
Permanent
N
157
157
32
32
Mean degree
0.497
0.637
3.125
2.500
Standard deviation
(0.965)
(1.415)
(4.030)
(2.700)
Signii cance of dif erence between mean degrees
Mann-Whitney
Wilcoxon rank sum test
W
8166.5
8613
66.5
20
p
- value
0.695
0.668
0.008
0.000
Note:
One-sided tests are performed with H
0
as no dif erence between samples and H
1
in the direction of the
observed dif erences.
In the last column of both tables the permanent innovators themselves (fourth column
in Tables 17.5 and 17.6) show a signii cant increase in linkages through cooperation
(from 2.563 to 3.938) and especially in scientist mobility (from 0.938 to 2.500). Thus,
parallel to the increased technological overlap in this group, the connectedness among
the incumbents becomes more intense over time.
The i rst column in both tables regards the comparison of the connectedness between
exiting and entering innovators within their respective group. The exiting innovators
show signii cantly more linkages through cooperation than the entering group (3.084
versus 2.242) and slightly, but not signii cantly more linkages through scientist mobility
(0.561 versus 0.497). The second and third columns report the mean degree between
permanent and exiting innovators in P1 and between permanent and entering innova-
tors in P2. The two columns dif er with respect to the group of actors for which this
index is computed, for the exiting or entering innovators in column 2 and for the per-
manents in column 3. For the
co
-network in column 2, we i nd that entering innovators
cooperate signii cantly more with the permanent ones than the exiting innovators did
(1.516 versus 0.710). With respect to the
sm
-network, entering innovators have also
more linkages through scientist mobility (0.637 versus 0.514) even though not to a
signii cant degree.
Summarizing these results, innovative entrants in Jena seem to be better integrated
into the network of personal relations than actors who, for whatever reasons, stopped
innovating. This i nding is consistent with results of Powell et al. (1999) that the network
position has an important inl uence on i rm performance. The observations regarding
the connectedness of entering and exiting innovators within their group are not contra-
dictive to our argument. Actors that enter such a network are certainly more aware of
