I have a file that look at ratings that teacher X gives to teacher Y and the date it occurs
clear
rating_id RatingTeacher RatedTeacher Rating Date
1 15 12 1 "1/1/2010"
2 12 11 2 "1/2/2010"
3 14 11 3 "1/2/2010"
4 14 13 2 "1/5/2010"
5 19 11 4 "1/6/2010"
5 11 13 1 "1/7/2010"
end
I want to look in the history to see how many times the RatingTeacher had been rated at the time they make the rating and the cumulative score. The result would look like this.
rating_id RatingTeacher RatedTeacher Rating Date TimesRated CumulativeRating
1 15 12 1 "1/1/2010" 0 0
2 12 11 2 "1/2/2010" 1 1
3 14 11 3 "1/2/2010" 0 0
4 14 13 2 "1/5/2010" 0 0
5 19 11 4 "1/6/2010" 0 0
5 11 13 1 "1/7/2010" 3 9
end
I have been merging the dataset with itself to get this to work, and it is fine. I was wondering if there was a more efficient way to do this within the file
In your input data, I guess that the last rating_id should be 6 and that dates are MDY. Statalist members are asked to use dataex (SSC) to set up data examples. This isn't Statalist but there is no reason for lower standards to apply. See the Statalist FAQ
I rarely see even programmers be precise about what they mean by "efficient", whether it means fewer lines of code, less use of memory, more speed, something else or is just some all-purpose term of praise. This code loops over observations, which can certainly be slow for large datasets. More in this paper
We can't compare with your merge solution because you don't give the code.
clear
input rating_id RatingTeacher RatedTeacher Rating str8 SDate
1 15 12 1 "1/1/2010"
2 12 11 2 "1/2/2010"
3 14 11 3 "1/2/2010"
4 14 13 2 "1/5/2010"
5 19 11 4 "1/6/2010"
6 11 13 1 "1/7/2010"
end
gen Date = daily(SDate, "MDY")
sort Date
gen Wanted = .
quietly forval i = 1/`=_N' {
count if Date < Date[`i'] & RatedT == RatingT[`i']
replace Wanted = r(N) in `i'
}
list, sep(0)
+---------------------------------------------------------------------+
| rating~d Rating~r RatedT~r Rating SDate Date Wanted |
|---------------------------------------------------------------------|
1. | 1 15 12 1 1/1/2010 18263 0 |
2. | 2 12 11 2 1/2/2010 18264 1 |
3. | 3 14 11 3 1/2/2010 18264 0 |
4. | 4 14 13 2 1/5/2010 18267 0 |
5. | 5 19 11 4 1/6/2010 18268 0 |
6. | 6 11 13 1 1/7/2010 18269 3 |
+---------------------------------------------------------------------+
The building block is that the rater and ratee are a pair. You can use egen's group() to give a unique ID to each rater ratee pair.
egen pair = group(rater ratee)
bysort pair (date): timesRated = _n
Related
I need to do this:
table 1:
ID Cod.
1 20
2 102
4 30
7 10
9 201
10 305
table 2:
ID Cod.
1 20
2 50
3 15
4 30
5 25
7 10
10 300
Now, I got a table like this with an outer join:
ID Cod. ID1 Cod1.
1 20 1 20
2 50 . .
. . 2 102
3 15 . .
4 30 4 30
5 25 . .
7 10 7 10
. . 9 201
10 300 . .
. . 10 305
Now I want to add a flag that tell me if the ID have common values, so:
ID Cod. ID1 Cod1. FLag_ID Flag_cod:
1 20 1 20 0 0
2 50 . . 0 1
. . 2 102 0 1
3 15 . . 1 1
4 30 4 30 0 0
5 25 . . 1 1
7 10 7 10 0 0
. . 9 201 1 1
10 300 . . 0 1
. . 10 305 0 1
I would like to know how can I get the flag_ID, specifically to cover the cases of ID = 2 or ID=10.
Thank you
You can group by a coalescence of id in order to count and compare details.
Example
data table1;
input id code ##; datalines;
1 20 2 102 4 30 7 10 9 201 10 305
;
data table2;
input id code ##; datalines;
1 20 2 50 3 15 4 30 5 25 7 10 10 300
;
proc sql;
create table got as
select
table2.id, table2.code
, table1.id as id1, table1.code as code1
, case
when count(table1.id) = 1 and count(table2.id) = 1 then 0 else 1
end as flag_id
, case
when table1.code - table2.code ne 0 then 1 else 0
end as flag_code
from
table1
full join
table2
on
table2.id=table1.id and table2.code=table1.code
group by
coalesce(table2.id,table1.id)
;
You might also want to look into
Proc COMPARE with BY
I have a dataset with only variable values:
clear
input value new_var
1 1
3 3
5 5
30 1
40 3
50 5
11 1
12 3
13 5
end
How can I generate a new variable new_var containing a repeating sequence of the first three observations in value?
Many ways to do it: here are two:
clear
input value new_var
1 1
3 3
5 5
30 1
40 3
50 5
11 1
12 3
13 5
end
egen index = seq(), to(3)
generate wanted = value[index]
generate direct = cond(mod(_n, 3) == 1, 1, cond(mod(_n, 3) == 2, 3, 5))
list, sep(3)
+-------------------------------------------+
| value new_var index wanted direct |
|-------------------------------------------|
1. | 1 1 1 1 1 |
2. | 3 3 2 3 3 |
3. | 5 5 3 5 5 |
|-------------------------------------------|
4. | 30 1 1 1 1 |
5. | 40 3 2 3 3 |
6. | 50 5 3 5 5 |
|-------------------------------------------|
7. | 11 1 1 1 1 |
8. | 12 3 2 3 3 |
9. | 13 5 3 5 5 |
+-------------------------------------------+
I have a large Stata dataset that contains the following variables: year, state, household_id, individual_id, partner_id, and race. Here is an example of my data:
year state household_id individual_id partner_id race
1980 CA 23 2 1 3
1980 CA 23 1 2 1
1990 NY 43 4 2 1
1990 NY 43 2 4 1
Note that, in the above table, column 1 and 2 are married to each other.
I want to create a variable that is one if the person is in an interracial marriage.
As a first step, I used the following code
by household_id year: gen inter=0 if race==race[partner_id]
replace inter=1 if inter==.
This code worked well but gave the wrong result in a few cases. As an alternative, I created a string variable identifying each user and its partner, using
gen id_user=string(household_id)+"."+string(individual_id)+string(year)
gen id_partner=string(household_id)+"."+string(partner_id)+string(year)
What I want to do now is to create something like what vlookup does in Excel: for each column, save locally the id_partner, find it in the id_user and find their race, and compare it with the race of the original user.
I guess it should be something like this?
gen inter2==1 if (find race[idpartner]) == (race[iduser])
The expected output should be like this
year state household_id individual_id partner_id race inter2
1980 CA 23 2 1 3 1
1980 CA 23 1 2 1 1
1990 NY 43 4 2 1 0
1990 NY 43 2 4 1 0
I don't think you need anything so general. As you realise, the information on identifiers suffices to find couples, and that in turn allows comparison of race for the people in each couple.
In the code below _N == 2 is meant to catch data errors, such as one partner but not the other being an observation in the dataset or repetitions of one partner or both.
clear
input year str2 state household_id individual_id partner_id race
1980 CA 23 2 1 3
1980 CA 23 1 2 1
1990 NY 43 4 2 1
1990 NY 43 2 4 1
end
generate couple_id = cond(individual_id < partner_id, string(individual_id) + ///
" " + string(partner_id), string(partner_id) + ///
" " + string(individual_id))
bysort state year household_id couple_id : generate mixed = race[1] != race[2] if _N == 2
list, sepby(household_id) abbreviate(15)
+-------------------------------------------------------------------------------------+
| year state household_id individual_id partner_id race couple_id mixed |
|-------------------------------------------------------------------------------------|
1. | 1980 CA 23 2 1 3 1 2 1 |
2. | 1980 CA 23 1 2 1 1 2 1 |
|-------------------------------------------------------------------------------------|
3. | 1990 NY 43 4 2 1 2 4 0 |
4. | 1990 NY 43 2 4 1 2 4 0 |
+-------------------------------------------------------------------------------------+
This idea is documented in this article. The link gives free access to a pdf file.
I have incremental data elements that I want to summarize. I'm pulling the incremental data into a matrix object just fine, but I need to summarize them by cumulating across columns (within the Row)
What I'm seeing:
Column: 1 2 3 4 5
Row |-----------------------------------------
1 | 10 15 5 4 1
2 | 12 12 3 1
3 | 10 9 6
4 | 9 15
5 | 11
What I want to see:
Column: 1 2 3 4 5
Row |-----------------------------------------
1 | 10 25 30 34 35
2 | 12 24 27 28
3 | 10 19 25
4 | 9 24
5 | 11
What I've tried, this just returns the incremental data (as if I just pointed it to [INC_AMT]:
Cum_Loss = CALCULATE(
SUM('Table1'[INC_AMT]),
FILTER(All (Table1[ColNum]), Table1[ColNum] <= max(Table1[Column])))
Give this measure a try:
PERIODIC INCREMENTAL SUM = CALCULATE
(
SUM('TestData'[INC_AMT])
, FILTER(
ALLSELECTED(TestData)
, and(
TestData[ColNum] <= max(TestData[ColNum])
, TestData[RowNum] = max(TestData[RowNum])
)
)
)
I found it helpful to not think about the measures in a matrix perspective. Transform it to a table and you see that one way to think about it is that it's just a cumulative sum where 'Row Number' is also the same. So, add that requirement to your filter and... presto.
I am trying to create instruments from a three-dimensional panel dataset, as included below:
input firm year market price comp_avg
1 2000 10 1 .
3 2000 10 2 .
3 2001 10 3 .
1 2002 10 4 .
3 2002 10 5 .
1 2000 20 6 .
3 2000 20 7 .
1 2001 20 8 .
2 2001 20 9 .
3 2001 20 10 .
1 2002 20 20 .
2 2002 20 30 .
3 2002 20 40 .
2 2000 30 50 .
1 2001 30 60 .
2 2001 30 70 .
1 2002 30 80 .
2 2002 30 90 .
end
The instrument I am trying to create is the lagged (year-1) average price of a firm's competitors (those in the same market) in each market the firm operates in in a given year.
At the moment, I have some code that does the job, but I am hoping that I am missing something and can do this in a more clear or efficient way.
Here is the code:
// for each firm
qui levelsof firm, local(firms)
qui foreach f in `firms' {
// find all years for that firm
levelsof year if firm == `f', local(years)
foreach y in `years' {
// skip first year (because there is no lagged data)
if `y' == 2000 {
continue
}
// find all markets in that year
levelsof market if firm == `f' & year == `y', local(mkts)
local L1 = `y'-1
foreach m in `mkts' {
// get average of all compeitors in that market in the year prior
gen temp = firm != `f' & year == `L1' & market == `m'
su price if temp
replace comp_avg = r(mean) if firm == `f' & market == `m' & year == `y'
drop temp
}
}
}
The data I am working with are reasonably large (~1 million obs) so the faster the better.
clear
input firm year market price
1 2000 10 1
3 2000 10 2
3 2001 10 3
1 2002 10 4
3 2002 10 5
1 2000 20 6
3 2000 20 7
1 2001 20 8
2 2001 20 9
3 2001 20 10
1 2002 20 20
2 2002 20 30
3 2002 20 40
2 2000 30 50
1 2001 30 60
2 2001 30 70
1 2002 30 80
2 2002 30 90
end
bysort firm market (year) : gen Lprice = price[_n-1] if year - year[_n-1] == 1
bysort market year : egen total = total(Lprice)
bysort market year : egen count = count(Lprice)
gen mean_others = (total - cond(missing(Lprice), 0, Lprice)) ///
/ (count - cond(missing(Lprice), 0, 1))
sort market year
list market year firm price Lprice mean_others total count, sepby(market year)
+--------------------------------------------------------------------------+
| market year firm price Lprice price mean_o~s total count |
|--------------------------------------------------------------------------|
1. | 10 2000 1 1 . 1 . 0 0 |
2. | 10 2000 3 2 . 2 . 0 0 |
|--------------------------------------------------------------------------|
3. | 10 2001 3 3 2 3 . 2 1 |
|--------------------------------------------------------------------------|
4. | 10 2002 1 4 . 4 3 3 1 |
5. | 10 2002 3 5 3 5 . 3 1 |
|--------------------------------------------------------------------------|
6. | 20 2000 3 7 . 7 . 0 0 |
7. | 20 2000 1 6 . 6 . 0 0 |
|--------------------------------------------------------------------------|
8. | 20 2001 2 9 . 9 6.5 13 2 |
9. | 20 2001 3 10 7 10 6 13 2 |
10. | 20 2001 1 8 6 8 7 13 2 |
|--------------------------------------------------------------------------|
11. | 20 2002 1 20 8 20 9.5 27 3 |
12. | 20 2002 3 40 10 40 8.5 27 3 |
13. | 20 2002 2 30 9 30 9 27 3 |
|--------------------------------------------------------------------------|
14. | 30 2000 2 50 . 50 . 0 0 |
|--------------------------------------------------------------------------|
15. | 30 2001 2 70 50 70 . 50 1 |
16. | 30 2001 1 60 . 60 50 50 1 |
|--------------------------------------------------------------------------|
17. | 30 2002 2 90 70 90 60 130 2 |
18. | 30 2002 1 80 60 80 70 130 2 |
+--------------------------------------------------------------------------+
My approach breaks it down:
Calculate the previous price for the same firm and market. (#1 could also be done by declaring a (firm, market) pair a panel.)
The mean of other values (here previous prices) in the same market and year is the (sum of others MINUS this price) divided by (number of others MINUS 1).
#2 needs a modification as if this price is missing, you need to subtract 0 from both numerator and denominator. Stata's normal rules would render sum MINUS missing as missing, but this firm's previous price might be unknown, yet others in the same market might have known prices.
Note: There are small ways of speeding up your code, but this should be faster (so long as it is correct).
EDIT: Another solution (2 lines) using rangestat (must be installed using ssc inst rangestat):
bysort firm market (year) : gen Lprice = price[_n-1] if year - year[_n-1] == 1
rangestat Lprice, interval(year 0 0) by(market) excludeself