Dear Satalis,

I hope you are well. I would like to ask please regarding the problem of 'not concave' iteration. I have a dataset for 300 firms, one of the firms appears to be an outlier. When I excluded the outlier (i.e. to be only 299 firms) from the multinomial regression analysis (mlogit) the analysis iteration took a long time to perform the iteration and showed non-concavity in some iteration process. How to solve this problem please? Important to mention that when the outlier is not excluded the regression runs perfect but I got small value for the marginal effects results (for instance, 3.94E) for only one of the dependent variable estimation.



. mlogit App_status i.I_sec i.AF_LEG i.AF_AGE i.AF_SIZE i.I_loct2 i.I_expt2 i.AF_GRWT i.BO_GEN i.BO_CIT i.BO_AGE i.ow_Exper2 i.BO_FINT i.BO_EDU i.CR_LEN i.CR
> _BS1 i.CR_BS2 i.CR_BS3 i.CR_BS4 i.CR_BS5 i.CR_BS6 i.CR_BS7 i.CR_BS8 i.CR_SAT i.DE_ADS1 i.DE_ADS2 i.DE_ADS3 i.DE_ADS4 i.DE_ADS5 i.DE_ADS6 i.DE_ADS72 i.EI_BP i.EI_AUDFR

Iteration 0: log likelihood = -376.13767
Iteration 1: log likelihood = -240.52371
Iteration 2: log likelihood = -204.10375
Iteration 3: log likelihood = -190.49561
Iteration 4: log likelihood = -182.16412
Iteration 5: log likelihood = -174.29973
Iteration 6: log likelihood = -169.14731
Iteration 7: log likelihood = -167.60249
Iteration 8: log likelihood = -167.36518
Iteration 9: log likelihood = -167.30934
Iteration 10: log likelihood = -167.29729
Iteration 11: log likelihood = -167.29478
Iteration 12: log likelihood = -167.29422
Iteration 13: log likelihood = -167.29408
Iteration 14: log likelihood = -167.29405
Iteration 15: log likelihood = -167.29405 (not concave)
Iteration 16: log likelihood = -167.29405 (not concave)
Iteration 17: log likelihood = -167.29405 (not concave)
Iteration 18: log likelihood = -167.29405 (not concave)
Iteration 19: log likelihood = -167.29405 (not concave)
Iteration 20: log likelihood = -167.29405 (not concave)
Iteration 21: log likelihood = -167.29405 (not concave)
Iteration 22: log likelihood = -167.29405 (not concave)
Iteration 23: log likelihood = -167.29405 (not concave)
Iteration 24: log likelihood = -167.29405 (not concave)
Iteration 25: log likelihood = -167.29405 (not concave)
Iteration 26: log likelihood = -167.29405 (not concave)
Iteration 27: log likelihood = -167.29405 (not concave)
Iteration 28: log likelihood = -167.29405 (not concave)
Iteration 29: log likelihood = -167.29405 (not concave)
Iteration 30: log likelihood = -167.29405 (not concave)
Iteration 31: log likelihood = -167.29405 (not concave)
Iteration 32: log likelihood = -167.29405 (not concave)
Iteration 33: log likelihood = -167.29405 (not concave)
Iteration 34: log likelihood = -167.29405 (not concave)
Iteration 35: log likelihood = -167.29405 (not concave)
Iteration 36: log likelihood = -167.29405 (not concave)
Iteration 37: log likelihood = -167.29405 (not concave)
Iteration 38: log likelihood = -167.29405 (not concave)
Iteration 39: log likelihood = -167.29405 (not concave)
Iteration 40: log likelihood = -167.29405 (not concave)
Iteration 41: log likelihood = -167.29405 (not concave)
Iteration 42: log likelihood = -167.29405 (not concave)
Iteration 43: log likelihood = -167.29405 (not concave)
Iteration 44: log likelihood = -167.29405 (not concave)
Iteration 45: log likelihood = -167.29405 (not concave)
Iteration 46: log likelihood = -167.29405 (not concave)
Iteration 47: log likelihood = -167.29405 (not concave)
Iteration 48: log likelihood = -167.29405 (not concave)
Iteration 49: log likelihood = -167.29405 (not concave)
Iteration 50: log likelihood = -167.29405 (not concave)
Iteration 51: log likelihood = -167.29405 (not concave)
Iteration 52: log likelihood = -167.29405 (not concave)
Iteration 53: log likelihood = -167.29405 (not concave)
Iteration 54: log likelihood = -167.29405 (not concave)
Iteration 55: log likelihood = -167.29405 (not concave)
Iteration 56: log likelihood = -167.29405 (not concave)
Iteration 57: log likelihood = -167.29405 (not concave)
Iteration 58: log likelihood = -167.29405 (not concave)

--Break--
r(1);




Could you please advise on how to solve the problem of the non-concavity with mlogit analysis?


Appreciate your kind help and cooperation

Best regards,
Rabab