_Table 7: Maximum Likelihood Estimates of the Stochastic Frontier_

||**Variables**|**(1)**|**(2)**|**(3)**|**(4)**|**(5)**|**(6)**|**(7)**|**(8)**|
|---|---|---|---|---|---|---|---|---|---|
|||0.12**|0.19**|0.21**|0.24**|0.21**|0.23**|0.20**|0.23**|
|β1|Area|(0.03)|(0.03)|(0.02)|(0.02)|(0.01)|(0.02)|(0.03)|(0.02)|
||Bth Lth|0.51**|0.38**|0.41**|0.43**|0.42**|0.46**|0.39**|0.44**|
|β2|er eng|(0.04)|(0.04)|(0.03)|(0.02)|(0.02)|(0.03)|(0.05)|(0.01)|
||Mbil/Q C|0.13**|0.25**|0.22**|0.19**|0.21**|0.23**|0.18**|0.22**|
|β3|oeuay ranes|(0.04)|(0.04)|(0.04)|(0.04)|(0.04)|(0.04)|(0.03)|(0.04)|
|β|STS Gantr Cranes|0.56**|0.68**|0.58**|0.49**|0.52**|0.48**|0.54**|0.49**|
|4|y|(0.04)|(0.04)|(0.03)|(0.05)|(0.04)|(0.02)|(0.03)|(0.02)|
|β|Li Td|0.04**|0.02*|0.03**|0.01|-0.02**|-0.02**|-0.03**|-0.02**|
|5|near ren|(0.01)|(0.01)|(0.01)|(0.01)|(0.00)|(0.01)|(0.00)|(0.00)|
||Shi’ C||0.75**|0.63**|0.60**|0.79**|0.70**|0.86**|0.67**|
|γ1|ps ranes||(0.08)|(0.06)|(0.05)|(0.05)|(0.12)|(0.06)|(0.04)|
||Thi||0.49**|0.40**|0.38**|0.39**|0.31**|0.45**|0.31**|
|γ2|ransspment||(0.07)|(0.07)|(0.06)|(0.06)|(0.10)|(0.09)|(0.02)|
||il|||0.38**|0.39**|0.17**|0.31**|0.10|0.29**|
|γ3|Termna Type|||(0.06)|(0.06)|(0.06)|(0.06)|(0.06)|(0.05)|
||GDP||||-0.05*|-0.08**|-0.06|-0.10**|-0.05**|
|γ4|||||(0.02)|(0.01)|(0.05)|(0.02)|(0.01)|
||||||058**|059**|074**|055**|069**|
|γ5|Connectivity||||.<br>|.<br>|.<br>|.<br>|.<br>|
||||||(0.11)|(0.03)|(0.10)|(0.04)|(0.07)|
||Td||||0.13|0.12**|0.20|0.05|0.24**|
|γ6|rae||||(0.09)|(0.04)|(0.16)|(0.08)|(0.05)|
||Cii|-0.14|-0.10|-0.13|-0.06*|-0.07**|-0.04*|-0.08**|-0.01|
|γ7|rss|(0.11)|(0.10)|(0.08)|(0.02)|(0.02)|(0.02)|(0.02)|(0.01)|
||C|7.55**|6.95**|6.95**|5.00**|6.04**|4.63**|7.08**|4.61**|
|α|onstant|(0.41)|(0.37)|(0.27)|(0.54)|(0.63)|(1.16)|(0.97)|(0.30)|
|||0.07|-8.24|0.78**|0.70**|1.65**|1.35|4.55**|1.21**|
|δ1|Constant|(0.75)|(23.27)|(0.13)|(0.09)|(0.22)|(1.84)|(1.30)|(0.14)|
||l|||||-0.22|-0.11|||
|δ2|Landord|||||013|014|||
|||||||(.)|(.)|||
|δ|Corrution|||||-0.11|-0.30|||
|3|p|||||(0.16)|(0.25)|||
|||||||-035*||-058**||
|δ4|Terminal Type|||||.<br>(0.14)||.<br>(0.21)||
||||||||0.03|-0.32*||
|δ5|GDP per capita||||||(0.22)|(0.14)||
|δ|South America||||||0.06|-0.22|-0.11|
|6|||||||(0.14)|(0.17)|(0.12)|
|δ|Transshipment||||||-0.23||-0.34*|
|7|||||||(0.29)||(0.15)|
|δ|Td|||||-0.08**|-0.06*|-0.09**|-0.05**|
|8|ren|||||(0.02)|(0.02)|(0.03)|(0.02)|
||<sup>_2_</sup>|1.02**|2.38|0.89**|0.90**|0.88**|0.86**|0.92**|0.87**|
||_σ_<br>_u_|(0.19)|(2.73)|(0.06)|(0.06)|(0.05)|(0.05)|(0.07)|(0.05)|
||<sup>_2_</sup>|0.44**|0.44**|0.11**|0.00|0.00|0.00|0.00|0.00|
||_σ_<br>_v_|(0.07)|(0.06)|(0.03)|(0.00)|(0.00)|(0.00)|(0.00)|(0.00)|
||_λ_|2.31**|5.42*|8.49**|11833**|8527**|10448**|6467**|5176**|
|||(0.18)|(2.69)|(0.06)|(0.06)|(0.05)|(0.05)|(0.07)|(0.05)|
|**_Obs_**|**_ervations_**|**599**|**599**|**599**|**566**|**566**|**566**|**566**|**566**|
|**_Nu_**|**_mber of Ports_**|**67**|**67**|**67**|**63**|**63**|**63**|**63**|**63**|
|||Standar|d Errors in|Parenthese|*p<005|**p<001||||
||||<br>Source:|<br>Authors’ c|. .,<br>alculations.|..<br>||||

Specifications (2) to (8) include a proxy for the use of ships’ cranes. This binary variable is highly significant and positive, confirming the intuition that the use of cranes mounted on vessels is a determinant of port throughput in Latin America. Disregarding this dummy would cause a potential omitted variable bias in the model, affecting the estimated parameters and the efficiency results, 16