When can academic researchers rest? An event history analysis on researchers’ research productivity and promotion in academia from 1980 to 2016 in Japan

Figures & data

Table 1. Descriptive statistics in this study.

	(1) Descriptive statistics of all variables				(2) Descriptive statistics of researchers who get professor
	Overall	Male	Female	T-test	Overall	Male	Female	T-test
	Mean (St.Dev.)	Mean (St.Dev.)	Mean (St.Dev.)		Mean (St.Dev.)	Mean (St.Dev.)	Mean (St.Dev.)
Tenure	17.057 (8.198)	17.382 (8.251)	15.503 (7.756)	***	16.844 (6.931)	17.049 (6.884)	15.608 (7.093)	***
Scopus journal articles	10.543 (25.510)	12.012 (27.357)	3.529 (11.179)	***	11.643 (25.213)	12.751 (26.487)	4.958 (13.675)	***
Non-Scopus journal articles	50.814 (75.787)	54.958 (81.025)	31.019 (36.715)	***	60.555 (83.436)	64.711 (88.309)	35.486 (34.454)	***
Books	7.704 (15.489)	7.878 (16.189)	6.875 (11.543)	***	9.714 (20.205)	9.779 (20.989)	9.318 (14.631)
Conference presentation	39.533 (94.317)	42.140 (100.283)	27.080 (56.256)	***	31.946 (86.900)	33.913 (92.646)	20.080 (34.230)	***
Awards	1.819 (4.229)	1.955 (4.442)	1.171 (2.926)	***	1.525 (3.769)	1.622 (3.949)	0.945 (2.336)	***
competitive research funding	4.047 (7.109)	4.115 (7.377)	3.720 (5.646)	***	5.329 (8.129)	5.357 (8.337)	5.164 (6.751)
Period of academic performance 0	4.236 (4.201)	4.153 (4.191)	4.631 (4.227)		5.502 (5.012)	5.405 (5.026)	6.087 (4.893)
N	14,014	11,588	2,426		2,187	1,876	311

Figure 1. Average number of research results per year by researchers.

Table 2. Cox regressions on the hazard of attaining a professorship.

	(1) Controls only	(2)Academic performance added	(3) Gender added	(4) Interval added
	Haz. Ratio (Std. Err.)	Haz. Ratio (Std. Err.)	Haz. Ratio (Std. Err.)	Haz. Ratio (Std. Err.)
Scopus journal articles (time-t)		1.006 (0.001)***	1.006 (0.001)***	1.006 (0.001)***
Non-Scopus journal articles (time-t)		1.000 (0.000)	1.000 (0.000)	0.999 (0.000)
Books (time-t)		1.006 (0.001)***	1.006 (0.001)***	1.006 (0.002)***
Conference presentation (time-t)		1.000 (0.000)	1.000 (0.000)	0.999 (0.000)
Awards (time-t)		1.005 (0.007)	1.005 (0.007)	1.004 (0.007)
competitive research funding (time-t)		1.026 (0.002)***	1.026 (0.002)***	1.026 (0.002)***
Female			0.976(0.083)	0.984(0.084)
Period of zero academic performance				0.985 (0.007)**
Academic field(reference: General Studies)
Science and engineering	0.714 (0.059)***	0.719 (0.060)***	0.718 (0.060)***	0.714 (0.060)***
Medical and biological	0.766 (0.059)***	0.753 (0.060)***	0.753 (0.060)***	0.750 (0.060)***
Humanities and Social Sciences	1.064 (0.082)	1.148 (0.093)*	1.151 (0.093)*	1.163 (0.095)*
Prestige graduation	1.024 (0.004)***	1.020 (0.004)***	1.020 (0.004)***	1.020 (0.004)***
Log likelihood	−11165.52	−11077.688	−11077.648	−11075.421
AIC	22339.04	22175.38	22177.3	22174.84
BIC	22378.87	22274.95	22286.82	22294.33
Number of Events	1,360	1,360	1,360	1,360
N (Persons)	14,014	14,014	14,014	14,014
N (Persons-Year)	2,39,132	2,39,132	2,39,132	2,39,132

Table 3. Analysis on the influence of the timing of research pauses.

	(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)
	Haz. Ratio (Std. Err.)	Haz. Ratio (Std. Err.)	Haz. Ratio (Std. Err.)	Haz. Ratio (Std. Err.)	Haz. Ratio (Std. Err.)	Haz. Ratio (Std. Err.)	Haz. Ratio (Std. Err.)	Haz. Ratio (Std. Err.)
Term = Period of absence
Term 1	0.853 (0.049)***
Term 2		1.017 (0.058)
Term 3			0.990 (0.059)
Term 4				0.947 (0.059)
Term 5					0.827 (0.053)***
Term 6						0.831 (0.056)***
Term 7							1.005 (0.071)
Term 8								0.909 (0.121)
Scopus journal articles (time-t)	1.006 (0.001)***	1.006 (0.001)***	1.006 (0.001)***	1.006 (0.001)***	1.006 (0.001)***	1.006 (0.001)***	1.006 (0.001)***	1.006 (0.001)***
Non-Scopus journal articles (time-t)	0.999 (0.000)	1.000 (0.000)	1.000 (0.000)	1.000 (0.000)	0.999 (0.000)	0.999 (0.000)	1.000 (0.000)	1.000 (0.000)
Books (time-t)	1.006 (0.002)***	1.006 (0.001)***	1.006 (0.001)***	1.006 (0.002)***	1.006 (0.002)***	1.006 (0.001)***	1.006 (0.001)***	1.006 (0.001)***
Conference presentation (time-t)	0.999 (0.000)	1.000 (0.000)	1.000 (0.000)	1.000 (0.000)	1.000 (0.000)	1.000 (0.000)	1.000 (0.000)	1.000 (0.000)
Awards (time-t)	1.005 (0.007)	1.005 (0.007)	1.005 (0.007)	1.005 (0.007)	1.004 (0.007)	1.004 (0.007)	1.005 (0.007)	1.005 (0.007)
Competitive research funding (time-t)	1.026 (0.002)***	1.026 (0.002)***	1.026 (0.002)***	1.026 (0.002)***	1.026 (0.002)***	1.026 (0.002)***	1.026 (0.002)***	1.026 (0.002)***
Female	0.983 (0.084)	0.975 (0.083)	0.977 (0.083)	0.979 (0.083)	0.984 (0.084)	0.978 (0.083)	0.976 (0.083)	0.975 (0.083)
Academic field(reference: General Studies)
Science and engineering	0.712 (0.059)***	0.718 (0.060)***	0.717 (0.060)***	0.716 (0.060)***	0.715 (0.060)***	0.717 (0.060)***	0.718 (0.060)***	0.718 (0.060)***
Medical and biological	0.753 (0.060)***	0.753 (0.060)***	0.753 (0.060)***	0.752 (0.060)***	0.748 (0.059)***	0.753 (0.060)***	0.753 (0.060)***	0.753 (0.060)***
Humanities and Social Sciences	1.161 (0.094)*	1.149 (0.093)*	1.152 (0.094)*	1.157 (0.094)*	1.164 (0.095)*	1.157 (0.094)*	1.151 (0.093)*	1.151 (0.093)*
Prestige graduation	1.021 (0.004)***	1.020 (0.004)***	1.020 (0.004)***	1.020 (0.004)***	1.020 (0.004)***	1.020 (0.004)***	1.020 (0.004)***	1.020 (0.004)***
Log likelihood	−11073.75	−11077.6	−11077.63	−11077.27	−11073.13	−11073.73	−11077.65	−11077.38
AIC	22171.49	22179.21	22179.27	22178.53	22170.26	22171.45	22179.29	22178.77
BIC	22290.98	22298.69	22298.75	22298.01	22289.74	22290.94	22298.77	22298.25
Number of Events	1,360	1,360	1,360	1,360	1,360	1,360	1,360	1,360
N (Persons)	14,014	14,014	14,014	14,014	14,014	14,014	14,014	14,014
N (Persons-Year)	2,39,132	2,39,132	2,39,132	2,39,132	2,39,132	2,39,132	2,39,132	2,39,132