Dear Statalisters,
I am trying to getting familiar with the principal component analysis in order to apply it to a dataset whose features I described in this Statalist post:
https://www.statalist.org/forums/for...on-individuals
Amongst my variables, there are some that are continuous, others that are ordinal, and others that are dummies. From what I understood by reading different sources, such as these:
https://onlinelibrary.wiley.com/doi/...1.2008.00309.x
I should resort to polychoricpca.
I also read this:
https://www.statalist.org/forums/for...ca?view=thread
and I tried to run the following commands on my database:
,
which returns the following output:
Afterwards I ran this command:
and obtained the following results:
What puzzles me, and I do apologise if my question is silly, is why when I use the
there is not a panel showing the Principal components (eigenvectors). I am inclined to think that this could be related to my lack of strong knowledge on the topic.
I would be very grateful if anyone could provide me an insight.
Many thanks.
Marco
I am trying to getting familiar with the principal component analysis in order to apply it to a dataset whose features I described in this Statalist post:
https://www.statalist.org/forums/for...on-individuals
Amongst my variables, there are some that are continuous, others that are ordinal, and others that are dummies. From what I understood by reading different sources, such as these:
https://onlinelibrary.wiley.com/doi/...1.2008.00309.x
I should resort to polychoricpca.
I also read this:
https://www.statalist.org/forums/for...ca?view=thread
and I tried to run the following commands on my database:
Code:
pca practicality-driv_pleas
which returns the following output:
Code:
. pca practicality-driv_pleas Principal components/correlation Number of obs = 870 Number of comp. = 20 Trace = 20 Rotation: (unrotated = principal) Rho = 1.0000 -------------------------------------------------------------------------- Component | Eigenvalue Difference Proportion Cumulative -------------+------------------------------------------------------------ Comp1 | 7.02921 4.61705 0.3515 0.3515 Comp2 | 2.41216 1.16462 0.1206 0.4721 Comp3 | 1.24754 .189893 0.0624 0.5344 Comp4 | 1.05764 .251995 0.0529 0.5873 Comp5 | .805648 .101337 0.0403 0.6276 Comp6 | .704311 .0593641 0.0352 0.6628 Comp7 | .644947 .0197066 0.0322 0.6951 Comp8 | .625241 .0390891 0.0313 0.7263 Comp9 | .586152 .0240978 0.0293 0.7556 Comp10 | .562054 .0200735 0.0281 0.7837 Comp11 | .54198 .028251 0.0271 0.8108 Comp12 | .513729 .0362875 0.0257 0.8365 Comp13 | .477442 .0270003 0.0239 0.8604 Comp14 | .450441 .016936 0.0225 0.8829 Comp15 | .433505 .00178447 0.0217 0.9046 Comp16 | .431721 .0151015 0.0216 0.9262 Comp17 | .416619 .036927 0.0208 0.9470 Comp18 | .379692 .0311164 0.0190 0.9660 Comp19 | .348576 .0171863 0.0174 0.9834 Comp20 | .33139 . 0.0166 1.0000 -------------------------------------------------------------------------- Principal components (eigenvectors) -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Variable | Comp1 Comp2 Comp3 Comp4 Comp5 Comp6 Comp7 Comp8 Comp9 Comp10 Comp11 Comp12 Comp13 Comp14 Comp15 Comp16 Comp17 Comp18 -------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ practicality | 0.2437 -0.0352 0.2588 0.1652 -0.1023 -0.3278 0.0369 -0.0374 -0.0613 -0.6074 -0.0068 -0.4662 0.2493 -0.1695 -0.1266 -0.0706 0.0530 0.1201 planning | 0.1970 -0.2483 0.3637 0.0555 -0.0530 0.1194 -0.1421 0.4696 0.0352 0.2862 0.3424 -0.0288 -0.1115 -0.5228 0.0447 0.0152 -0.0324 0.0920 anxiety | 0.2212 0.0170 0.4158 0.2559 -0.0604 -0.2954 -0.1364 0.0330 0.2856 -0.0576 -0.2117 0.4173 -0.2933 0.2462 -0.2444 0.1658 0.0381 -0.2239 long_dist | 0.1917 -0.3195 0.2872 -0.0140 -0.0561 0.0105 0.3373 0.0057 -0.2858 0.0852 0.1058 0.3420 0.4398 0.3578 0.1033 -0.0524 -0.2099 0.1946 ch_time | 0.2339 -0.2097 0.2201 -0.0925 -0.0096 0.1251 -0.0124 -0.1155 -0.3058 0.3423 -0.5344 -0.3989 -0.0656 0.0818 0.1441 -0.0142 0.1744 -0.2855 ch_prob | 0.2389 -0.2493 -0.1753 0.0692 -0.1061 0.2116 -0.3041 -0.2445 0.2022 0.1677 -0.1337 -0.0244 0.0663 -0.0081 -0.4602 -0.1299 0.1589 0.3921 ins_ch | 0.1989 -0.3342 -0.0920 0.0605 0.0653 0.1649 0.0802 -0.4191 0.3758 -0.2137 -0.0242 0.2520 0.0896 -0.3199 0.4472 -0.0639 0.0767 -0.2006 elec_plant | 0.2427 -0.1497 -0.2643 0.1498 -0.3136 0.0331 -0.2874 -0.0172 0.0299 -0.0132 0.3197 -0.2622 -0.0819 0.3203 0.0963 0.0137 -0.4924 -0.3242 elec_bill | 0.2393 -0.0030 -0.3742 0.1677 -0.4379 0.0071 0.1233 0.1899 -0.1242 -0.0031 -0.0128 0.1373 -0.0483 0.1068 0.0704 0.0827 0.3706 0.2690 safety | 0.2415 0.3226 0.0588 0.0036 -0.0777 -0.1840 0.0189 -0.0394 0.1373 0.2237 0.0527 0.0034 -0.1236 0.0106 0.2146 -0.4286 0.0092 0.0108 tech_risk | 0.2203 0.3567 0.0451 0.0286 0.0361 -0.2351 0.1390 -0.2145 0.1094 0.2604 0.0889 -0.1056 -0.0197 0.0129 0.1879 -0.2461 -0.0433 0.2535 env_adv | 0.1900 0.2583 0.1576 -0.4381 -0.2213 0.2527 -0.0060 0.1119 0.3392 -0.1278 -0.1604 -0.1104 0.0399 0.1007 0.2415 0.4803 -0.1011 0.2341 batt_disp | 0.2181 0.1846 0.0740 -0.5055 -0.1196 0.0633 -0.0013 -0.2199 -0.0497 0.0495 0.3557 0.1011 0.2352 -0.0615 -0.4072 -0.0351 0.1959 -0.3694 batt_dur | 0.2610 0.0082 -0.0565 -0.2151 0.0661 -0.0872 -0.1576 -0.2376 -0.5589 -0.2306 0.0647 0.2273 -0.4949 -0.1706 0.0957 0.1335 -0.0686 0.1636 pur_price | 0.2047 -0.2678 -0.1090 -0.1774 0.3372 0.0357 0.4619 0.1992 0.2096 -0.1207 0.2238 -0.2161 -0.3925 0.2838 -0.1017 -0.0671 0.2315 -0.0315 elec_cost | 0.2450 0.0987 -0.3241 -0.0671 -0.1396 -0.0484 0.3174 0.3535 -0.0249 -0.0537 -0.3937 0.1591 0.0752 -0.3301 -0.1849 -0.1493 -0.2770 -0.2573 resid_value | 0.2367 0.0571 -0.1085 -0.1587 0.4441 0.0339 -0.5149 0.3749 -0.0269 -0.1921 -0.0998 0.1301 0.2494 0.2025 0.1682 -0.2692 0.1024 0.0113 maint | 0.2460 -0.0619 -0.2418 0.0159 0.4386 -0.3634 0.0323 -0.1000 0.0730 0.2907 -0.0199 -0.0732 0.1735 -0.1104 -0.1217 0.4645 -0.2460 0.1079 accel | 0.1990 0.3029 -0.0604 0.4388 0.1234 0.1542 0.0300 0.0393 -0.1549 0.0549 0.1903 -0.0148 0.1965 -0.0093 0.1188 0.3429 0.3890 -0.2544 driv_pleas | 0.1787 0.2863 0.1346 0.2964 0.2474 0.6139 0.1533 -0.1010 -0.0671 -0.1254 -0.0394 -0.0076 -0.1097 0.0092 -0.2199 -0.0988 -0.3185 0.1004 -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ------------------------------------------------ Variable | Comp19 Comp20 | Unexplained -------------+--------------------+------------- practicality | -0.0395 -0.0600 | 0 planning | -0.0545 0.0685 | 0 anxiety | -0.0532 0.0982 | 0 long_dist | 0.1516 -0.0670 | 0 ch_time | -0.1184 0.0429 | 0 ch_prob | 0.3667 -0.0527 | 0 ins_ch | -0.1011 0.0369 | 0 elec_plant | 0.0319 0.0685 | 0 elec_bill | -0.5106 0.0335 | 0 safety | 0.0295 -0.6888 | 0 tech_risk | 0.0741 0.6577 | 0 env_adv | 0.1287 -0.0585 | 0 batt_disp | -0.2137 0.0491 | 0 batt_dur | 0.1863 -0.0231 | 0 pur_price | 0.1251 0.0013 | 0 elec_cost | 0.2593 0.0896 | 0 resid_value | -0.0966 0.1058 | 0 maint | -0.2653 -0.1746 | 0 accel | 0.4238 -0.0388 | 0 driv_pleas | -0.3218 -0.0329 | 0 ------------------------------------------------
Afterwards I ran this command:
Code:
polychoricpca practicality-driv_pleas
Code:
Polychoric correlation matrix practicality planning anxiety long_dist ch_time ch_prob ins_ch elec_plant elec_bill safety tech_risk env_adv batt_disp practicality 1 planning .46887165 1 anxiety .55476727 .48296498 1 long_dist .46718179 .58813472 .43427449 1 ch_time .48750757 .54248733 .43528707 .58396926 1 ch_prob .41067713 .46715181 .36692686 .47536231 .55263095 1 ins_ch .40712897 .43675706 .33544393 .55435099 .505425 .64638532 1 elec_plant .44775213 .41857401 .3406354 .40976515 .43772118 .63096593 .52643512 1 elec_bill .38509483 .26585289 .3117979 .31739859 .34538106 .52971132 .41715367 .61974414 1 safety .43710027 .21463469 .47680019 .12978229 .30172985 .25737162 .12181734 .35575943 .44107087 1 tech_risk .41233114 .12749909 .41954204 .0815096 .2505261 .19523019 .0862999 .27916593 .37593173 .7234901 1 env_adv .31372293 .20176292 .31846783 .11551468 .28917119 .1911353 .09696787 .2261309 .28673824 .52815186 .49866812 1 batt_disp .35063497 .24051664 .29363291 .26200293 .33750162 .30937666 .20248101 .30267165 .31955302 .54546077 .52057275 .59619518 1 batt_dur .46910848 .34595909 .40099893 .3968134 .49034134 .46767487 .4267432 .48399172 .48482918 .48230543 .44452145 .39767814 .54208202 pur_price .38079009 .44053879 .26335672 .50233421 .47543892 .51078059 .55815531 .45157092 .39087453 .18019573 .14964534 .18476263 .28845316 elec_cost .38165003 .2268896 .29591694 .25708499 .34473421 .42301636 .33167376 .46663746 .62026213 .51626612 .46303236 .41464156 .43505393 resid_value .37487362 .32515586 .33632106 .25735509 .37568142 .41826521 .31720273 .41010176 .37430398 .45391778 .39345303 .39296702 .42958995 maint .40452551 .31327526 .34195969 .36205555 .42634147 .51607562 .48102522 .48034615 .44800222 .41086188 .43248485 .22309007 .35368913 accel .37370698 .1551999 .36747058 .05985803 .17803794 .21656976 .09798908 .32355482 .44439632 .55706164 .57254742 .31050701 .31133116 driv_pleas .32189344 .16196697 .3518798 .09673567 .22172954 .19446546 .10801442 .20142901 .25762503 .49091961 .50256195 .37894014 .32330302 batt_dur pur_price elec_cost resid_value maint accel driv_pleas batt_dur 1 pur_price .44953416 1 elec_cost .4985904 .40738182 1 resid_value .52230607 .41945232 .47256824 1 maint .51978832 .5372825 .51017407 .52462419 1 accel .35318229 .09837516 .41800321 .38888505 .3790175 1 driv_pleas .32474894 .11625503 .33979756 .34236231 .23654472 .60780512 1 Principal component analysis k | Eigenvalues | Proportion explained | Cum. explained ----+---------------+------------------------+------------------ 1 | 8.229478 | 0.411474 | 0.411474 2 | 2.616316 | 0.130816 | 0.542290 3 | 1.270536 | 0.063527 | 0.605816 4 | 1.051264 | 0.052563 | 0.658380 5 | 0.753465 | 0.037673 | 0.696053 6 | 0.647771 | 0.032389 | 0.728441 7 | 0.564983 | 0.028249 | 0.756691 8 | 0.544444 | 0.027222 | 0.783913 9 | 0.487707 | 0.024385 | 0.808298 10 | 0.471218 | 0.023561 | 0.831859 11 | 0.450944 | 0.022547 | 0.854406 12 | 0.437860 | 0.021893 | 0.876299 13 | 0.384210 | 0.019210 | 0.895510 14 | 0.350997 | 0.017550 | 0.913060 15 | 0.344459 | 0.017223 | 0.930283 16 | 0.323430 | 0.016172 | 0.946454 17 | 0.310614 | 0.015531 | 0.961985 18 | 0.276303 | 0.013815 | 0.975800 19 | 0.251480 | 0.012574 | 0.988374 20 | 0.232521 | 0.011626 | 1.000000
Code:
polychoricpca practicality-driv_pleas
I would be very grateful if anyone could provide me an insight.
Many thanks.
Marco
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