Dear Statalist members,
Long time observer, first time poster here. I learned a great deal from your posts & answers over the years, and I now have a specific question I can’t quite figure out.
I am trying to do a sort of a multilevel modelling with “mixed” command, using an unbalanced panel dataset. The overall setting is this:
DV: Firm-level corporate social responsibility performance (rating)
IV: Individual top management team characteristic, while controlling for CEO’s attribute
To elaborate, I am trying to see if a certain characteristic of non-CEO top management team members (TMT) will have an impact on firm-level outcome over and beyond that of the CEO. Let’s call the TMT / CEO characteristic “Trait A”.
The issue is that I need to include the individual TMT member’s Trait A separately into the model, but the outcome is observed at the firm level. So the model needs to include each of the individual TMT member’s Trait A separately into the model, which would be nested within each firm.
To do that, I have created multiple identifiers within the dataset: ID for individual TMT members, ID for each individual-TMT pair, ID for each firm (and industry and year identifiers as well). The code I used to run the initial model is like the following (variable names are swapped, but the code itself is identical to one I used):
So, the question is this: Am I running the multilevel models correctly? The model runs and gives out result tables, but I am not sure if I’m specifying the models correctly given what I am trying to test.
More specifically, some of the confusing I’m having revolves around issues such as: Am I using the correct grouping variables in each of the levels? Should I try to take more levels into account (e.g., industry)? Can I or should I control for the year effect in the way I’m including them in the model now?
The code I am using currently is this:
firm_outcome: DV
i.year: year indicator
i.industry: industry indicator
ceo_trait_A: controlling for CEO’s Trait A
ceo_control_1: additional control for relevant CEO attribute
ceo_control_2: additional control for relevant CEO attribute
tmt_control_1: controlling for same attribute in individual TMT members with the CEO
tmt_control_2: controlling for same attribute in individual TMT members with the CEO
tmt_trait_A: Variable of interest. Individual TMT member’s Trait A
firm_id: ID for each firm
tmt_firm_pair_id: ID for each individual TMT member and firm pair (e.g., TMT A-Firm A = 0001, TMT A-Firm B=0002, …)
The results look like the following:
I also run the model with an interaction term added, as I’m interested in moderating effect of a certain variable that is based on the relationship between the CEO and the non-CEO TMT member. The code looks like the following:
*ceo_tmt_relationship: Relationship variable specific for each TMT member and the CEO for each firm.
The result looks like the following:
To reiterate, the question is this: Am I running the multilevel models correctly? The model runs and gives out result tables, but I am not sure if I’m specifying the models correctly given what I am trying to test.
More specifically, some of the confusing I’m having revolves around issues such as: Am I using the correct grouping variables in each of the levels? Should I try to take more levels into account (e.g., industry)? Can I or should I control for the year effect in the way I’m including them in the model now?
I am aware of the small size of the covariates for the variables of interest in the model. I think that can be taken care of by changing the scale of the variables later on.
Any insight on how I am running the models would be much appreciated! Thank you for your time and consideration in advance.
Long time observer, first time poster here. I learned a great deal from your posts & answers over the years, and I now have a specific question I can’t quite figure out.
I am trying to do a sort of a multilevel modelling with “mixed” command, using an unbalanced panel dataset. The overall setting is this:
DV: Firm-level corporate social responsibility performance (rating)
IV: Individual top management team characteristic, while controlling for CEO’s attribute
To elaborate, I am trying to see if a certain characteristic of non-CEO top management team members (TMT) will have an impact on firm-level outcome over and beyond that of the CEO. Let’s call the TMT / CEO characteristic “Trait A”.
The issue is that I need to include the individual TMT member’s Trait A separately into the model, but the outcome is observed at the firm level. So the model needs to include each of the individual TMT member’s Trait A separately into the model, which would be nested within each firm.
To do that, I have created multiple identifiers within the dataset: ID for individual TMT members, ID for each individual-TMT pair, ID for each firm (and industry and year identifiers as well). The code I used to run the initial model is like the following (variable names are swapped, but the code itself is identical to one I used):
So, the question is this: Am I running the multilevel models correctly? The model runs and gives out result tables, but I am not sure if I’m specifying the models correctly given what I am trying to test.
More specifically, some of the confusing I’m having revolves around issues such as: Am I using the correct grouping variables in each of the levels? Should I try to take more levels into account (e.g., industry)? Can I or should I control for the year effect in the way I’m including them in the model now?
The code I am using currently is this:
Code:
mixed firm_outcome i.year i.industry ceo_trait_A ceo_control_1 ceo_control_2 /// tmt_control_1 tmt_control2 tmt_trait_A || firm_id: || tmt_firm_pair_id:
i.year: year indicator
i.industry: industry indicator
ceo_trait_A: controlling for CEO’s Trait A
ceo_control_1: additional control for relevant CEO attribute
ceo_control_2: additional control for relevant CEO attribute
tmt_control_1: controlling for same attribute in individual TMT members with the CEO
tmt_control_2: controlling for same attribute in individual TMT members with the CEO
tmt_trait_A: Variable of interest. Individual TMT member’s Trait A
firm_id: ID for each firm
tmt_firm_pair_id: ID for each individual TMT member and firm pair (e.g., TMT A-Firm A = 0001, TMT A-Firm B=0002, …)
The results look like the following:
Code:
Performing EM optimization ... Performing gradient-based optimization: Iteration 0: log likelihood = -49047.968 Iteration 1: log likelihood = -49047.832 Iteration 2: log likelihood = -49047.832 Computing standard errors ... Mixed-effects ML regression Number of obs = 118,607 Grouping information ------------------------------------------------------------- | No. of Observations per group Group variable | groups Minimum Average Maximum ----------------+-------------------------------------------- firm_id | 2,648 1 44.8 238 tmt_firm_pair_id | 29,321 1 4.0 22 ------------------------------------------------------------- Wald chi2(36) = 4458.11 Log likelihood = -49047.832 Prob > chi2 = 0.0000 ------------------------------------------------------------------------------------------ firm_outcome | Coefficient Std. err. z P>|z| [95% conf. interval] -------------------------+---------------------------------------------------------------- year | 1993 | .00556 .0095535 0.58 0.561 -.0131645 .0242845 1994 | .0049174 .0096436 0.51 0.610 -.0139837 .0238184 1995 | .0118385 .0097604 1.21 0.225 -.0072916 .0309686 1996 | .0102722 .0099117 1.04 0.300 -.0091543 .0296987 1997 | .0033965 .0100088 0.34 0.734 -.0162203 .0230133 1998 | -.0056598 .0100506 -0.56 0.573 -.0253586 .0140391 1999 | -.0076267 .0101267 -0.75 0.451 -.0274746 .0122213 2000 | -.0067193 .010276 -0.65 0.513 -.0268599 .0134212 2001 | .0684061 .0098819 6.92 0.000 .0490379 .0877744 2002 | .0720901 .0098876 7.29 0.000 .0527108 .0914695 2003 | .1515418 .0095472 15.87 0.000 .1328296 .170254 2004 | .1528703 .0096387 15.86 0.000 .1339787 .1717618 2005 | .1554403 .0098182 15.83 0.000 .136197 .1746837 2006 | .1579207 .0096669 16.34 0.000 .1389739 .1768675 2007 | .1783125 .0096435 18.49 0.000 .1594115 .1972134 2008 | .1764963 .0096883 18.22 0.000 .1575075 .1954851 2009 | .1761126 .0097561 18.05 0.000 .1569909 .1952343 2010 | .2589668 .0098262 26.35 0.000 .2397079 .2782258 2011 | .2891228 .0098784 29.27 0.000 .2697616 .3084841 2012 | .2920214 .0099677 29.30 0.000 .2724851 .3115578 2013 | .2948403 .010078 29.26 0.000 .2750878 .3145928 | industry | 2 | .1142829 .1502563 0.76 0.447 -.1802139 .4087798 3 | .1267328 .1636033 0.77 0.439 -.1939237 .4473893 4 | .3235708 .1465069 2.21 0.027 .0364226 .610719 5 | .2442008 .1479205 1.65 0.099 -.0457179 .5341196 6 | .2979823 .152505 1.95 0.051 -.000922 .5968866 7 | .3295068 .1486819 2.22 0.027 .0380957 .620918 8 | .3907518 .1470049 2.66 0.008 .1026275 .6788762 9 | .3193841 .1472104 2.17 0.030 .0308571 .6079111 10 | .272765 .1943922 1.40 0.161 -.1082366 .6537667 | ceo_trait_A | .0004901 .0000709 6.92 0.000 .0003513 .000629 ceo_control_1 | -.0001374 .0002338 -0.59 0.557 -.0005958 .0003209 tmt_control_1 | .0003279 .0001958 1.68 0.094 -.0000557 .0007116 ceo_control_2 | -7.14e-06 7.91e-07 -9.03 0.000 -8.69e-06 -5.59e-06 tmt_control_2 | 5.97e-06 1.78e-06 3.35 0.001 2.48e-06 9.46e-06 tmt_trait_A | .0001101 .000061 1.80 0.071 -9.47e-06 .0002296 _cons | -.4758617 .1462839 -3.25 0.001 -.762573 -.1891505 ------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------ Random-effects parameters | Estimate Std. err. [95% conf. interval] -----------------------------+------------------------------------------------ firm_id: Identity | var(_cons) | .1396965 .0040593 .1319627 .1478836 -----------------------------+------------------------------------------------ tmt_firm_pair_id: Identity | var(_cons) | .0377478 .000635 .0365235 .0390132 -----------------------------+------------------------------------------------ var(Residual) | .1020949 .0004819 .1011547 .1030438 ------------------------------------------------------------------------------ LR test vs. linear model: chi2(2) = 97906.16 Prob > chi2 = 0.0000 Note: LR test is conservative and provided only for reference.
Code:
mixed firm_outcome i.year i.industry ceo_trait_A ceo_control_1 ceo_control_2 /// tmt_control_1 tmt_control2 c.ceo_tmt_relationship##c.tmt_trait_A || firm_id: || tmt_firm_pair_id:
The result looks like the following:
Code:
Performing EM optimization ... Performing gradient-based optimization: Iteration 0: log likelihood = -49047.392 Iteration 1: log likelihood = -49047.255 Iteration 2: log likelihood = -49047.255 Computing standard errors ... Mixed-effects ML regression Number of obs = 118,607 Grouping information ------------------------------------------------------------- | No. of Observations per group Group variable | groups Minimum Average Maximum ----------------+-------------------------------------------- firm_id | 2,648 1 44.8 238 tmt_firm_pair_id | 29,321 1 4.0 22 ------------------------------------------------------------- Wald chi2(38) = 4459.44 Log likelihood = -49047.255 Prob > chi2 = 0.0000 ------------------------------------------------------------------------------------------------------------- firm_outcome | Coefficient Std. err. z P>|z| [95% conf. interval] --------------------------------------------+---------------------------------------------------------------- year | 1993 | .0054582 .0095541 0.57 0.568 -.0132675 .0241838 1994 | .0047473 .009645 0.49 0.623 -.0141566 .0236513 1995 | .0116 .009763 1.19 0.235 -.0075352 .0307352 1996 | .0099628 .0099159 1.00 0.315 -.0094721 .0293977 1997 | .0030361 .0100144 0.30 0.762 -.0165919 .022664 1998 | -.0059889 .0100554 -0.60 0.551 -.0256971 .0137194 1999 | -.0079909 .0101324 -0.79 0.430 -.02785 .0118682 2000 | -.0070383 .0102804 -0.68 0.494 -.0271876 .013111 2001 | .0681851 .0098844 6.90 0.000 .0488121 .0875581 2002 | .0718161 .0098913 7.26 0.000 .0524294 .0912028 2003 | .1512256 .0095522 15.83 0.000 .1325036 .1699475 2004 | .1525406 .0096443 15.82 0.000 .133638 .1714431 2005 | .1550779 .0098248 15.78 0.000 .1358218 .1743341 2006 | .1575569 .0096735 16.29 0.000 .1385971 .1765166 2007 | .1779621 .0096495 18.44 0.000 .1590493 .1968748 2008 | .1761081 .0096957 18.16 0.000 .1571049 .1951114 2009 | .1756895 .0097649 17.99 0.000 .1565507 .1948283 2010 | .2585263 .0098356 26.28 0.000 .2392489 .2778037 2011 | .2886516 .0098891 29.19 0.000 .2692694 .3080338 2012 | .2915076 .0099807 29.21 0.000 .2719459 .3110694 2013 | .2943222 .010091 29.17 0.000 .2745442 .3141002 | industry | 2 | .114184 .1502386 0.76 0.447 -.1802783 .4086462 3 | .1263998 .1635835 0.77 0.440 -.1942179 .4470175 4 | .3232903 .14649 2.21 0.027 .0361752 .6104054 5 | .243951 .1479034 1.65 0.099 -.0459343 .5338364 6 | .2977231 .1524874 1.95 0.051 -.0011467 .5965929 7 | .3292493 .1486642 2.21 0.027 .0378728 .6206257 8 | .3905855 .1469876 2.66 0.008 .1024951 .678676 9 | .3192203 .1471934 2.17 0.030 .0307266 .6077139 10 | .272194 .1943689 1.40 0.161 -.108762 .65315 | ceo_trait_A | .0004911 .0000709 6.93 0.000 .0003522 .00063 ceo_control_1 | -.0002068 .0002442 -0.85 0.397 -.0006854 .0002718 tmt_control_1 | .0001256 .0002788 0.45 0.652 -.0004209 .000672 ceo_control_2 | -7.14e-06 7.91e-07 -9.02 0.000 -8.69e-06 -5.59e-06 tmt_control_2 | 5.96e-06 1.78e-06 3.35 0.001 2.47e-06 9.45e-06 ceo_tmt_relationship | .0003316 .0003541 0.94 0.349 -.0003623 .0010256 tmt_trait_A | .0001271 .0000793 1.60 0.109 -.0000284 .0002826 | c.ceo_tmt_relationship#c.tmt_trait_A | -2.32e-06 6.91e-06 -0.34 0.737 -.0000159 .0000112 | _cons | -.4752772 .1462696 -3.25 0.001 -.7619604 -.188594 ------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------ Random-effects parameters | Estimate Std. err. [95% conf. interval] -----------------------------+------------------------------------------------ firm_id: Identity | var(_cons) | .1396593 .0040585 .131927 .1478447 -----------------------------+------------------------------------------------ tmt_firm_pair_id: Identity | var(_cons) | .0377418 .000635 .0365175 .0390072 -----------------------------+------------------------------------------------ var(Residual) | .1020966 .0004819 .1011564 .1030456 ------------------------------------------------------------------------------ LR test vs. linear model: chi2(2) = 97786.99 Prob > chi2 = 0.0000 Note: LR test is conservative and provided only for reference.
More specifically, some of the confusing I’m having revolves around issues such as: Am I using the correct grouping variables in each of the levels? Should I try to take more levels into account (e.g., industry)? Can I or should I control for the year effect in the way I’m including them in the model now?
I am aware of the small size of the covariates for the variables of interest in the model. I think that can be taken care of by changing the scale of the variables later on.
Any insight on how I am running the models would be much appreciated! Thank you for your time and consideration in advance.
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