Output interpretation summary(<plm_object>): T = 4-10

[nbadino]

I'm trying to estimate a simple model, but I don't know how to interpret T = 4-10. The time span is 2012-2021. Can somebody help?

Oneway (individual) effect Within Model

Call:
plm(formula = gdp_log ~ sum_log, data = pdata, model = "within")

Unbalanced Panel: n = 166, T = 4-10, N = 1644

Residuals:
      Min.    1st Qu.     Median    3rd Qu.       Max. 
-0.4469225 -0.0386242  0.0063501  0.0452923  0.5530283 

Coefficients:
         Estimate Std. Error t-value  Pr(>|t|)    
sum_log 0.2814691  0.0095728  29.403 < 2.2e-16 ***
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Total Sum of Squares:    17.006
Residual Sum of Squares: 10.727
R-Squared:      0.36922
Adj. R-Squared: 0.29833
F-statistic: 864.541 on 1 and 1477 DF, p-value: < 2.22e-16

[tappek]

T = 4 - 10 means your model has per individal between 4 to 10 observations for time periods. n is the number of individuals, N is the number of total information.

It is a line stemming from pdim, so you might want to look at ?plm::pdim for more details and examples.