Need help with merged data set

[MBlack732]

Hello!

For an assignment, we merged two data sets "bp" (which include subject, date of visit, SBP and DBP; there were multiple observations per subject) and "demog" (which include variables like date of birth, date of entering the study, marital status, education, smoking, and drinking). I need to make sure that the subjects are all under the age of 55 and the blood pressure readings considered are only from the first visit date. So far in my code I did:

LIBNAME BIST0535 "C:\Users\Paula\Desktop\BIST0535";

*Narrowing down blood pressure data to first visit only*

DATA BIST0535.bp_hw3_1;

                SET BIST0535.bp_hw3;

RUN;

PROC SORT Data=BIST0535.bp_hw3_1;

                BY subject;

RUN;

DATA BIST0535.bp_hw3_2;

                SET BIST0535.bp_hw3_1;

                BY subject;

                IF FIRST.subject;

RUN;

*Merging of Datasets and narrowing subject list to people younger than 55*

DATA BIST0535.HW3;

                SET BIST0535.demog_hw3 BIST0535.bp_hw3_2;

                age = (doe-dob)/365.25;

                IF age GT 55 THEN DELETE;

RUN;

*Looking at relationship between marital status and smoking/drinking*

PROC SORT DATA= BIST0535.HW3;

                BY marital;

RUN;

PROC FREQ DATA= BIST0535.HW3;

                TABLES smoke drink smoke*drink;

                BY marital;

                TITLE "HW3 Frequencies of smoke, drink, and smoke*drink by marital status";

RUN;

Now I want to look at the relationship between educational attainment (education) and blood pressure readings (SBP and DBP), by looking at the break down of frequencies, as I did above with marital and smoking/drinking. However it is not working and I believe it is because the way the data was merged. Even if the subject is the same, the variables from the two different original data sets are appearing on separate observations. Here is a section of the proc print (I italicized subject 1, as it exemplifies this issue):

Obs subject site gender dob doe smoke drink marital education dov dbp sbp age

1	.		.	.	.	.	.	.	14145	107	134	.
1	5	F	-1092	14069	0	2	3	3	.	.	.	41.5086
2	.		.	.	.	.	.	.	14447	115	143	.
3	.		.	.	.	.	.	.	14082	103	148	.
4	.		.	.	.	.	.	.	14632	87	110	.
4	1	F	892	14632	0	5	2	3	.	.	.	37.6181
5	.		.	.	.	.	.	.	14650	66	108	.
5	2	F	259	14558	0	2	1	2	.	.	.	39.1485
6	.		.	.	.	.	.	.	14520	75	133	.
6	4	F	1809	14429	1	2	3	3	.	.	.	34.5517
7	.		.	.	.	.	.	.	14813	87	131	.
7	3	M	-3979	14637	0	2	3	2	.	.	.	50.9678
8	.		.	.	.	.	.	.	14285	112	149	.
8	5	M	-3669	14285	0	4	2	3	.	.	.	49.1554
9	.		.	.	.	.	.	.	14865	84	123	.
9	3	F	2438	14618	0	3	3	3	.	.	.	33.3470
10	.		.	.	.	.	.	.	13967	88	120

HOW DO I FIX THIS PLEASE?

[Reeza · Accepted solution]

Always add comments so it's clear what you're trying to do in each step.

LIBNAME BIST0535 "C:\Users\Paula\Desktop\BIST0535";

 

*Narrowing down blood pressure data to first visit only*

DATA BIST0535.bp_hw3_1;

                SET BIST0535.bp_hw3;

RUN;

 

PROC SORT Data=BIST0535.bp_hw3_1;

                BY subject;

RUN;

 

DATA BIST0535.bp_hw3_2;

                SET BIST0535.bp_hw3_1;

                BY subject;
                 *this takes the first subject, but you likely want a sort by date to pick the first date. Since you didn't sort by date, it could be any of the dates not necessarily the first record. Visually verify the data to ensure you get the data correct;
                IF FIRST.subject;

RUN;

 

*Merging of Datasets and narrowing subject list to people younger than 55*

DATA BIST0535.HW3;
                *SET APPENDS, it does not merge. You need to change SET to MERGE;
                SET BIST0535.demog_hw3 BIST0535.bp_hw3_2;

                *No BY statement to merge by ID  - add one;

                age = (doe-dob)/365.25; * Use YRDIF() instead to calculate the age;

                IF age GT 55 THEN DELETE;

RUN;

 

Once you have those issues fixed, you should be closer to what you need.

---

@MBlack732 wrote:

Hello!

For an assignment, we merged two data sets "bp" (which include subject, date of visit, SBP and DBP; there were multiple observations per subject) and "demog" (which include variables like date of birth, date of entering the study, marital status, education, smoking, and drinking). I need to make sure that the subjects are all under the age of 55 and the blood pressure readings considered are only from the first visit date. So far in my code I did:

LIBNAME BIST0535 "C:\Users\Paula\Desktop\BIST0535";

*Narrowing down blood pressure data to first visit only*

DATA BIST0535.bp_hw3_1;

                SET BIST0535.bp_hw3;

RUN;

PROC SORT Data=BIST0535.bp_hw3_1;

                BY subject;

RUN;

DATA BIST0535.bp_hw3_2;

                SET BIST0535.bp_hw3_1;

                BY subject;

                IF FIRST.subject;

RUN;

*Merging of Datasets and narrowing subject list to people younger than 55*

DATA BIST0535.HW3;

                SET BIST0535.demog_hw3 BIST0535.bp_hw3_2;

                age = (doe-dob)/365.25;

                IF age GT 55 THEN DELETE;

RUN;

*Looking at relationship between marital status and smoking/drinking*

PROC SORT DATA= BIST0535.HW3;

                BY marital;

RUN;

PROC FREQ DATA= BIST0535.HW3;

                TABLES smoke drink smoke*drink;

                BY marital;

                TITLE "HW3 Frequencies of smoke, drink, and smoke*drink by marital status";

RUN;

Now I want to look at the relationship between educational attainment (education) and blood pressure readings (SBP and DBP), by looking at the break down of frequencies, as I did above with marital and smoking/drinking. However it is not working and I believe it is because the way the data was merged. Even if the subject is the same, the variables from the two different original data sets are appearing on separate observations. Here is a section of the proc print (I italicized subject 1, as it exemplifies this issue):

Obs subject site gender dob doe smoke drink marital education dov dbp sbp age

1	.		.	.	.	.	.	.	14145	107	134	.
1	5	F	-1092	14069	0	2	3	3	.	.	.	41.5086
2	.		.	.	.	.	.	.	14447	115	143	.
3	.		.	.	.	.	.	.	14082	103	148	.
4	.		.	.	.	.	.	.	14632	87	110	.
4	1	F	892	14632	0	5	2	3	.	.	.	37.6181
5	.		.	.	.	.	.	.	14650	66	108	.
5	2	F	259	14558	0	2	1	2	.	.	.	39.1485
6	.		.	.	.	.	.	.	14520	75	133	.
6	4	F	1809	14429	1	2	3	3	.	.	.	34.5517
7	.		.	.	.	.	.	.	14813	87	131	.
7	3	M	-3979	14637	0	2	3	2	.	.	.	50.9678
8	.		.	.	.	.	.	.	14285	112	149	.
8	5	M	-3669	14285	0	4	2	3	.	.	.	49.1554
9	.		.	.	.	.	.	.	14865	84	123	.
9	3	F	2438	14618	0	3	3	3	.	.	.	33.3470
10	.		.	.	.	.	.	.	13967	88	120

HOW DO I FIX THIS PLEASE?

---

[MBlack732]

Perfect! Thank you so much! Such a simple fix, I feel foolish that I missed it! Thanks again for the help!