. 2020 Aug 28;10:14232. doi: 10.1038/s41598-020-71009-7

Table 1.

Regression results.

	Dependent variable: prob (diversification)
	Full diversification		Within field diversfication		Between field diversfication
	Single	Multiple	Single	Multiple	Single	Multiple
	(i)	(ii)	(iii)	(iv)	(v)	(vi)
Knowledge relatedness	0.936***	0.688***	0.184***	0.121***	0.702***	0.511***
Knowledge relatedness	(0.003)	(0.009)	(0.005)	(0.013)	(0.003)	(0.011)
Social relatedness	2.827***	4.243***	2.272***	3.968***	2.914***	4.284***
Social relatedness	(0.006)	(0.019)	(0.008)	(0.021)	(0.008)	(0.021)
Field core-atomic	$-$ 0.332***	$-$ 0.428***	0.056**	$-$ 0.276***	$-$ 0.303***	$-$ 0.385***
Field core-atomic	(0.010)	(0.007)	(0.025)	(0.021)	(0.010)	(0.008)
Field core-classical	$-$ 0.490***	$-$ 0.477***	$-$ 1.001***	$-$ 0.932***	$-$ 0.313***	$-$ 0.328***
Field core-classical	(0.010)	(0.007)	(0.029)	(0.023)	(0.010)	(0.008)
Field core-cond. matter	$-$ 1.088***	$-$ 0.761***	$-$ 1.110***	$-$ 0.892***	$-$ 1.263***	$-$ 0.903***
Field core-cond. matter	(0.012)	(0.009)	(0.024)	(0.020)	(0.017)	(0.013)
Field core-general	$-$ 0.722***	$-$ 0.537***	$-$ 0.927***	$-$ 0.823***	$-$ 0.632***	$-$ 0.422***
Field core-general	(0.011)	(0.007)	(0.028)	(0.021)	(0.012)	(0.008)
Field core-hgh.energy	0.219***	0.168***	1.806***	1.176***	$-$ 0.360***	$-$ 0.060***
Field core-hgh.energy	(0.010)	(0.006)	(0.027)	(0.023)	(0.013)	(0.008)
Field core-interdisc	$-$ 0.557***	$-$ 0.553***	$-$ 0.357***	$-$ 0.724***	$-$ 0.365***	$-$ 0.367***
Field core-interdisc	(0.010)	(0.007)	(0.026)	(0.021)	(0.011)	(0.008)
Field core-nuclear	0.463***	0.164***	0.969***	0.692***	0.068***	$-$ 0.161***
Field core-nuclear	(0.010)	(0.006)	(0.024)	(0.021)	(0.011)	(0.009)
Field core-plasma	$-$ 0.269***	$-$ 0.419***	$-$ 0.155**	$-$ 0.361***	$-$ 0.074***	$-$ 0.256***
Field core-plasma	(0.013)	(0.008)	(0.068)	(0.058)	(0.015)	(0.009)
# of PACS	0.882***	0.806***	0.769***	0.497***	1.003***	0.944***
# of PACS	(0.002)	(0.003)	(0.005)	(0.004)	(0.004)	(0.004)
# of papers	0.010***	0.113***	0.065***	0.252***	$-$ 0.032***	0.050***
# of papers	(0.002)	(0.003)	(0.005)	(0.004)	(0.004)	(0.004)
# of co-authors	$-$ 0.406***	$-$ 0.347***	$-$ 0.240***	$-$ 0.145***	$-$ 0.488***	$-$ 0.444***
# of co-authors	(0.002)	(0.004)	(0.004)	(0.004)	(0.003)	(0.006)
PACS target popularity	1.130***	0.611***	1.370***	0.774***	1.108***	0.559***
PACS target popularity	(0.002)	(0.002)	(0.005)	(0.003)	(0.003)	(0.002)
$Δ$ crowd	0.239***	0.358***	0.131***	0.345***	0.320***	0.393***
$Δ$ crowd	(0.002)	(0.003)	(0.003)	(0.003)	(0.003)	(0.003)
$Δ$ PACS citations	$-$ 0.273***	$-$ 0.332***	$-$ 0.208***	$-$ 0.313***	$-$ 0.369***	$-$ 0.354***
$Δ$ PACS citations	(0.002)	(0.003)	(0.004)	(0.003)	(0.004)	(0.003)
$Δ$ field citations	$-$ 0.156***	$-$ 0.070***	✗	✗	$-$ 0.196***	$-$ 0.143***
$Δ$ field citations	(0.004)	(0.004)	(✗)	(✗)	(0.006)	(0.005)
KR:SR	$-$ 0.255***	$-$ 0.061***	$-$ 0.047***	$-$ 0.001	$-$ 0.234***	$-$ 0.067***
KR:SR	(0.004)	(0.010)	(0.007)	(0.013)	(0.005)	(0.011)
Constant	$-$ 3.812***	$-$ 5.903***	$-$ 1.882***	$-$ 4.250***	$-$ 4.168***	$-$ 6.165***
Constant	(0.010)	(0.020)	(0.022)	(0.028)	(0.010)	(0.022)
Observations	7,072,386	35,968,615	1,000,230	5,407,404	6,072,156	30,154,990
Log kikelihood	$-$ 1,086,281.000	$-$ 7,303,198.000	$-$ 334,697.300	$-$ 2,166,803.000	$-$ 716,398.900	$-$ 4,971,497.000
Akaike inf. crit.	2,172,600.000	14,606,434.000	669,430.600	4,333,642.000	1,432,836.000	9,943,033.000

Coefficients of the logistic regressions of Eq. (8), i.e. the model including the interaction term between knowledge and social relatedness, under different specialization settings. The table reports clustering corrected standard errors (in parenthesis) and significance level: *p < 0.1; **p < 0.05; ***p < 0.01. ✗: variable not included in the model.