Assigned Reading
- Read Chapter 14 in Statistical Analysis of Electronic Health
Records by Farrokh Alemi, 2020
- Practice based multilevel regression
Read►
Assignment
Submit assignments in Blackboard. Include in the first page a summary page. In the summary page
write statements comparing your work to answers given or videos. For
example, "I got the same answers as the Teach One video for question 1."
Question 1: The following simulated data show the
survival of patients in two tertiary medical centers and 3 community
hospitals. Should ambulances take trauma victims to tertiary
medical centers, by passing community hospitals?
Data►
R Code►
Answer by Debora Vittorio►
- Predict patient survival rates using patient-level variables:
(a) Presence of severe burns, (b) Head injury, (c) More than 65+
years old, (d) Male gender. Identify the intercept for each
hospital
- Regress unexplained variation in survival probability on
features of the hospital, including whether it is a tertiary medical
center (Yes=1, No=0), or has a dedicated burn unit (Yes=1, No=0).
|
Hospital |
Tertiary Center |
Has
Burn Unit |
|
A |
1 |
0 |
|
B |
1 |
1 |
|
C |
0 |
0 |
|
D |
0 |
0 |
|
E |
0 |
0 |
- Report the meaning of these two related regressions.
Question 2: In this problem, we approach multi-level
modeling through SQL. In particular, we address question 1 but this
time we use SQL instead of regression. These steps could be helpful:
- Select the data for one of the medical centers and contrast it to
the average of other centers.
- Use SQL to calculate survival rate for the hospital and the
average of other hospitals across strata. Each stratum is a
combination of patient conditions.
- Estimate the survival rate for each hospital at the situation
where all patient conditions are absent. This is done in two
steps. First, regress survival at one hospital on survival at
other hospitals. The intercept for this regression is the
estimated survival for the hospital when all patient conditions are
absent.
- Regress survival rates at different hospitals on distance and
percent satisfied at the hospital.
- Examine mortality rates at the center as a function of center's
distance to referral source and satisfaction of the patients in the
center.
| Medical Center |
Average
Travel
Distance |
Percent Satisfied |
|
Hospital 1 |
50 |
79 |
|
Hospital 2 |
80 |
82 |
|
Hospital 3 |
70 |
80 |
|
Hospital 4 |
70 |
79 |
|
Hospital 5 |
80 |
79 |
|
Hospital 6 |
70 |
83 |
|
Hospital 7 |
80 |
81 |
Use the instructor's last name as the password for the data.
Question 3: Using multi-level modeling,
calculate the expected length of stay for the clinician and peer group, after removing the effects of
previous Myocardial Infarction (MI) and Congestive Heart Failure (CHF).
Compare the performance of the clinician to the peer provider using the
intercepts estimated for each group.
|
Clinician's Patients
|
Peer Provider's Patients
|
|
Case
|
Previous MI
|
CHF
|
Length of stay
|
Case
|
Previous MI
|
CHF
|
Length of stay
|
|
1
|
MI
|
CHF
|
6
|
1
|
MI
|
CHF
|
5
|
|
2
|
MI
|
No CHF
|
5
|
2
|
MI
|
CHF
|
5
|
|
3
|
MI
|
CHF
|
6
|
3
|
No MI
|
CHF
|
4
|
|
4
|
MI
|
CHF
|
6
|
4
|
No MI
|
No CHF
|
3
|
|
5
|
MI
|
CHF
|
6
|
5
|
No MI
|
CHF
|
4
|
|
6
|
MI
|
No CHF
|
5
|
6
|
No MI
|
CHF
|
4
|
|
7
|
MI
|
CHF
|
6
|
7
|
MI
|
CHF
|
5
|
|
8
|
MI
|
No CHF
|
5
|
8
|
MI
|
CHF
|
5
|
|
9
|
MI
|
CHF
|
6
|
9
|
MI
|
CHF
|
5
|
|
10
|
MI
|
No CHF
|
5
|
10
|
MI
|
CHF
|
5
|
|
11
|
MI
|
CHF
|
6
|
11
|
MI
|
CHF
|
5
|
|
12
|
No MI
|
CHF
|
4
|
12
|
No MI
|
No CHF
|
3
|
|
13
|
No MI
|
CHF
|
4
|
13
|
No MI
|
CHF
|
4
|
|
14
|
No MI
|
CHF
|
4
|
14
|
No MI
|
CHF
|
4
|
|
15
|
MI
|
CHF
|
6
|
15
|
No MI
|
CHF
|
4
|
|
16
|
MI
|
CHF
|
6
|
16
|
No MI
|
CHF
|
4
|
|
17
|
MI
|
CHF
|
6
|
17
|
No MI
|
CHF
|
4
|
|
18
|
MI
|
No CHF
|
5
|
18
|
No MI
|
No CHF
|
3
|
|
19
|
MI
|
No CHF
|
5
|
19
|
MI
|
No CHF
|
4
|
|
20
|
MI
|
CHF
|
6
|
20
|
MI
|
CHF
|
5
|
|
|
|
|
|
21
|
MI
|
CHF
|
5
|
|
|
|
|
|
22
|
MI
|
CHF
|
5
|
|
|
|
|
|
23
|
MI
|
No CHF
|
4
|
|
|
|
|
|
24
|
No MI
|
CHF
|
4
|
More
For additional information (not part of the required reading), please see the following links:
- A practical guide to multi-level modeling
PubMed►
This page is part of the course on Comparative Effectiveness by Farrokh Alemi PhD Home►
Email►
|
