I have a panel of 1000 firms and I wish to generate two subsamples of
firms with relatively low and relatively high mvalue during our sample
period. The sample splits should be achieved as follows: each firm
should be assigned to a high (resp. low) category according to its
position in the first year it enters the sample relative to the median
across all firms in the first year they enter the sample. For example,
firm 1 was categorised as a high mvalue firm if its mvalue in 1948,
the first year firm XYZ entered the sample, was above the median
dividend payout ratio across all firms in the first year they entered
the sample. I would be very grateful I somebody could write me the
Stata commands useful to enter this particular sample splitting.
Here is a basic sample (just three companies).
company year invest mvalue kstock time
1 1935 317.6 3078.5 2.8 1
1 1936 391.8 4661.7 52.6 2
1 1937 410.6 5387.1 156.9 3
1 1938 257.7 2792.2 209.2 4
1 1939 330.8 4313.2 203.4 5
1 1940 461.2 4643.9 207.2 6
1 1941 512 4551.2 255.2 7
1 1942 448 3244.1 303.7 8
1 1943 499.6 4053.7 264.1 9
1 1944 547.5 4379.3 201.6 10
1 1945 561.2 4840.9 265 11
1 1946 688.1 4900.9 402.2 12
1 1947 547.5 3999 547.5 13
1 1948 321.6 5411 547.5 14
1 1949 . . . 15
1 1950 . . . 16
1 1951 . . . 17
1 1952 . . . 18
1 1953 . . . 19
1 1954 . . . 20
2 1935 . . . 1
2 1936 77.2 118 50.5 2
2 1937 44.6 156.2 118.1 3
2 1938 48.1 172.6 260.2 4
2 1939 74.4 186.6 312.7 5
2 1940 113 220.9 254.2 6
2 1941 91.9 118 261.4 7
2 1942 445.6 156.2 298.7 8
2 1943 48.1 172.6 48.1 9
2 1944 74.4 186.6 74.4 10
2 1945 113 220.9 113 11
2 1946 91.9 91.9 91.9 12
2 1947 . . . 13
2 1948 . . . 14
2 1949 . . . 15
2 1950 . . . 16
2 1951 . . . 17
2 1952 . . . 18
2 1953 . . . 19
2 1954 . . . 20
3 1935 61.3 61.3 61.3 1
3 1936 45 2015.8 104.4 2
3 1937 77.2 2803.3 118 3
3 1938 44.6 2039.7 156.2 4
3 1939 48.1 2256.2 172.6 5
3 1940 74.4 2132.2 186.6 6
3 1941 113 1834.1 220.9 7
3 1942 91.9 1588 287.8 8
3 1943 61.3 1749.4 319.9 9
3 1944 56.8 1687.2 321.3 10
3 1945 93.6 2007.7 319.6 11
3 1946 159.9 2208.3 346 12
3 1947 147.2 1656.7 456.4 13
3 1948 146.3 1604.4 543.4 14
3 1949 98.3 1431.8 618.3 15
3 1950 93.5 1610.5 647.4 16
3 1951 135.2 1819.4 671.3 17
3 1952 157.3 2079.7 726.1 18
3 1953 179.5 2371.6 800.3 19
3 1954 189.6 2759.9 888.9 20
....
Waiting for an help, thank you in advance to all.
Yours,
Nick
Alessandro
Alessandro Fiaschi
Dipartimento di Scienze Economiche, University of Rome "La Sapienza"
Via Cesalpino 12 - 00161 Rome (Italy)
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