The Airline Cost Data: First Difference or Fixed Effects

/*--------------------------------------------------------------

                    SAS Sample Library

        Name: panex02.sas
 Description: Example program from SAS/ETS User's Guide,
              The PANEL Procedure
       Title: The Airline Cost Data: First Difference or Fixed Effects
     Product: SAS/ETS
        Keys: panel data
        PROC: PANEL
       Notes:

--------------------------------------------------------------*/

data Airline;
   input Obs AirlineID T C Q PF LF;
   Year = T + 1969;
   lC   = log(C);
   lQ   = log(Q);
   lPF  = log(PF);
   label lC  = "Log Transformation of Costs";
   label lQ  = "Log Transformation of Quantity";
   label lPF = "Log Transformation of Price of Fuel";
   label LF  = "Load Factor (utilization index)";
datalines;
 1    1     1    1140640    0.95276     106650    0.53449
 2    1     2    1215690    0.98676     110307    0.53233
 3    1     3    1309570    1.09198     110574    0.54774
 4    1     4    1511530    1.17578     121974    0.54085
 5    1     5    1676730    1.16017     196606    0.59117
 6    1     6    1823740    1.17376     265609    0.57542
 7    1     7    2022890    1.29051     263451    0.59450
 8    1     8    2314760    1.39067     316411    0.59741
 9    1     9    2639160    1.61273     384110    0.63852
10    1    10    3247620    1.82544     569251    0.67629
11    1    11    3787750    1.54604     871636    0.60574
12    1    12    3867750    1.52790     997239    0.61436
13    1    13    3996020    1.66020     938002    0.63337
14    1    14    4282880    1.82231     859572    0.65012
15    1    15    4748320    1.93646     823411    0.62560
16    2     1     569292    0.52064     103795    0.49085
17    2     2     640614    0.53463     111477    0.47345
18    2     3     777655    0.65519     118664    0.50301
19    2     4     999294    0.79158     114797    0.51250
20    2     5    1203970    0.84295     215322    0.56678
21    2     6    1358100    0.85289     281704    0.55813
22    2     7    1501350    0.92284     304818    0.55880
23    2     8    1709270    1.00000     348609    0.57207
24    2     9    2025400    1.19845     374579    0.62476
25    2    10    2548370    1.34067     544109    0.62871
26    2    11    3137740    1.32624     853356    0.58915
27    2    12    3557700    1.24852    1003200    0.53261
28    2    13    3717740    1.25432     941977    0.52665
29    2    14    3962370    1.37177     856533    0.54016
30    2    15    4209390    1.38974     821361    0.52878
31    3     1     286298    0.26242     118788    0.52433
32    3     2     309290    0.26643     123798    0.53719
33    3     3     342056    0.30604     122882    0.58212
34    3     4     374595    0.32559     131274    0.57949
35    3     5     450037    0.34571     222037    0.60659
36    3     6     510412    0.36752     278721    0.60727
37    3     7     575347    0.40994     306564    0.58243
38    3     8     669331    0.44802     356073    0.57397
39    3     9     783799    0.53960     378311    0.65426
40    3    10     913883    0.53938     555267    0.63106
41    3    11    1041520    0.46797     850322    0.56924
42    3    12    1125800    0.45054    1015610    0.58968
43    3    13    1096070    0.46879     954508    0.58795
44    3    14    1198930    0.49440     886999    0.56539
45    3    15    1170470    0.49332     844079    0.57708
46    4     1     145167    0.08639     114987    0.43207
47    4     2     170192    0.09674     120501    0.43967
48    4     3     247506    0.14150     121908    0.48893
49    4     4     309391    0.16972     127220    0.48418
50    4     5     354338    0.17381     209405    0.52993
51    4     6     373941    0.16427     263148    0.53272
52    4     7     420915    0.17091     316724    0.54907
53    4     8     474017    0.17784     363598    0.55714
54    4     9     532590    0.19225     389436    0.61138
55    4    10     676771    0.24247     547376    0.64532
56    4    11     880438    0.25651     850418    0.61173
57    4    12    1052020    0.24966    1011170    0.58088
58    4    13    1193680    0.27392     951934    0.57205
59    4    14    1303390    0.37113     881323    0.59457
60    4    15    1436970    0.42141     831374    0.58553
61    5     1      91361    0.05103     118222    0.44288
62    5     2      95428    0.05265     116223    0.46247
63    5     3      98187    0.05635     115853    0.51912
64    5     4     115967    0.06695     129372    0.52933
65    5     5     138382    0.07031     243266    0.55780
66    5     6     156228    0.07396     277930    0.55618
67    5     7     183169    0.08495     317273    0.56933
68    5     8     210212    0.09547     358794    0.58347
69    5     9     274024    0.11981     397667    0.63182
70    5    10     356915    0.15005     566672    0.60472
71    5    11     432344    0.14401     848393    0.58792
72    5    12     524294    0.16930    1005740    0.61616
73    5    13     530924    0.17276     958231    0.60587
74    5    14     581447    0.18667     872924    0.59469
75    5    15     610257    0.21328     844622    0.63555
76    6     1      68978    0.03768     117112    0.44854
77    6     2      74904    0.03978     119420    0.47589
78    6     3      83829    0.04433     116087    0.50056
79    6     4      98148    0.05025     122997    0.50034
80    6     5     118449    0.05505     194309    0.52890
81    6     6     133161    0.05246     307923    0.49536
82    6     7     145062    0.05698     323595    0.51034
83    6     8     170711    0.06149     363081    0.51830
84    6     9     199775    0.06903     386422    0.54672
85    6    10     276797    0.09275     564867    0.55428
86    6    11     381478    0.11264     874818    0.51777
87    6    12     506969    0.15415    1013170    0.58005
88    6    13     633388    0.18646     930477    0.55602
89    6    14     804388    0.24685     851676    0.53779
90    6    15    1009500    0.30401     819476    0.52578
;

proc sort data = Airline;
   by AirlineID Year;
run;

proc panel data = Airline;
   id AirlineID Year;
   model lC = lQ lPF LF / fixtwo printfixed DW;
run;

proc panel data = Airline;
   id AirlineID Year;
   model lC = lQ lPF LF / fdtwo printfixed BW;
run;