I have the following problem with my unbalanced monthly panel data, where "permno" is the identifier for a company: I want to generate a new variable that captures the mean of the previous three quarters (in the next step I want to calculate the deviation from the mean, but that is not part of my question). If there is no data for the last three previous quarters available, I want the new variable to have a missing value. To give more context, the variable "cheq_new" is the quarterly accounting number Cash and Short-Term Investments. Because the data is published quarterly, each month per quarter has the same value.
Here is an example of the data:
Code:
* Example generated by -dataex-. To install: ssc install dataex clear input double permno float(number year month quarter cheq_new) 10000 1 1985 12 4 . 10000 2 1986 1 1 .743 10000 3 1986 2 1 .743 10000 4 1986 3 1 .743 10000 5 1986 4 2 .395 10000 6 1986 5 2 .395 10000 7 1986 6 2 .395 10000 8 1986 7 3 .425 10000 9 1986 8 3 .425 10000 10 1986 9 3 .425 10000 11 1986 10 4 .348 10000 12 1986 11 4 .348 10000 13 1986 12 4 .348 10000 14 1987 1 1 . 10000 15 1987 2 1 . 10000 16 1987 3 1 . 10000 17 1987 4 2 .341 10000 18 1987 5 2 .341 10000 19 1987 6 2 .341 10001 1 1985 12 4 . 10001 2 1986 1 1 .106 10001 3 1986 2 1 .106 10001 4 1986 3 1 .106 10001 5 1986 4 2 .746 10001 6 1986 5 2 .746 10001 7 1986 6 2 .746 10001 8 1986 7 3 .775 10001 9 1986 8 3 .775 10001 10 1986 9 3 .775 10001 11 1986 10 4 .649 10001 12 1986 11 4 .649 10001 13 1986 12 4 .649 10001 14 1987 1 1 .837 10001 15 1987 2 1 .837 10001 16 1987 3 1 .837 10001 17 1987 4 2 .729 10001 18 1987 5 2 .729 10001 19 1987 6 2 .729 10001 20 1987 7 3 .173 10001 21 1987 8 3 .173 10001 22 1987 9 3 .173 10001 23 1987 10 4 .754 10001 24 1987 11 4 .754 10001 25 1987 12 4 .754 10001 26 1988 1 1 .731 10001 27 1988 2 1 .731 10001 28 1988 3 1 .731 10001 29 1988 4 2 1.206 10001 30 1988 5 2 1.206 10001 31 1988 6 2 1.206 10001 32 1988 7 3 1.203 10001 33 1988 8 3 1.203 10001 34 1988 9 3 1.203 10001 35 1988 10 4 1.051 10001 36 1988 11 4 1.051 10001 37 1988 12 4 1.051 10001 38 1989 1 1 1.206 10001 39 1989 2 1 1.206 10001 40 1989 3 1 1.206 10001 41 1989 4 2 1.177 10001 42 1989 5 2 1.177 10001 43 1989 6 2 1.177 10001 44 1989 7 3 .731 10001 45 1989 8 3 .731 10001 46 1989 9 3 .731 10001 47 1989 10 4 .784 10001 48 1989 11 4 .784 10001 49 1989 12 4 .784 10001 50 1990 1 1 .756 10001 51 1990 2 1 .756 10001 52 1990 3 1 .756 10001 53 1990 4 2 1.356 10001 54 1990 5 2 1.356 10001 55 1990 6 2 1.356 10001 56 1990 7 3 1.025 10001 57 1990 8 3 1.025 10001 58 1990 9 3 1.025 10001 59 1990 10 4 .583 10001 60 1990 11 4 .583 10001 61 1990 12 4 .583 10001 62 1991 1 1 1.164 10001 63 1991 2 1 1.164 10001 64 1991 3 1 1.164 10001 65 1991 4 2 1.595 10001 66 1991 5 2 1.595 10001 67 1991 6 2 1.595 10001 68 1991 7 3 .566 10001 69 1991 8 3 .566 10001 70 1991 9 3 .566 10001 71 1991 10 4 1.17 10001 72 1991 11 4 1.17 10001 73 1991 12 4 1.17 10001 74 1992 1 1 1.341 10001 75 1992 2 1 1.341 10001 76 1992 3 1 1.341 10001 77 1992 4 2 1.1 10001 78 1992 5 2 1.1 10001 79 1992 6 2 1.1 10001 80 1992 7 3 3.89 10001 81 1992 8 3 3.89 end
Best regards,
Steven
0 Response to Average (Mean) of previous quarters
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