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Introduction to Biostatistics PhD programs
Takumi Saegusa
University of WashingtonDepartment of Biostatistics
April 17 2013
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Outline
What is Biostatistics?
Applying to Graduate Schools
Survival Guide
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Biostatistics?
WHAT IS BIOSTATISTICS?
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Biostatistics?
Statistics = Theory + Methods + Applications
Balanced Development: Math + Science + YOUMethodological research
Theory Methods Applications
Biostatistics
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Biostatistics?
Sequential Clinical trial
FDA requires clinical trials for a new drug approval
Sample size calculation
Mean vs Median (Doesn’t matter? Really?)
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Biostatistics?
Sequential Clinical trial
Should we stop early if a new drug is “clearly” beneficial or harmful?
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Biostatistics?
Network estimation
Central Dogma: Gene → RNA → Protein
Abundance of thousands of mRNAs is measured by microarray at once
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Biostatistics?
Network estimation
Estimate covariance matrix in high dimension
Regularization (penalized MLE)
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Biostatistics?
Air Pollution Study
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Biostatistics?
Air Pollution Study
Data are scattered over a regionData are scattered over time points (different measurements)Data are measured with errors
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Biostatistics?
HIV clinical trials
censoring: no information after time T = information that she livemore than Tdeath: censoring or outcome?
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Biostatistics?
HIV clinical trials
Breastfeeding was confirmed as a risk factor of the mother-to-childtransmission (MTCT) in a randomized clinical trial around 2000
WHO does not recommend mixed feeding (breastfeeding + formulafeeding)
T : time to infection
0 = t0 < t1 < t2 < . . . < tp: observation times
infection-free probability at time ti (no censoring):
S(ti ) = P(infection free more than time ti )
= P(T > ti )
= P(T ≥ ti+1)
= P(T ≥ ti+1|T ≥ ti )P(T ≥ ti |T ≥ ti−1) . . .
×P(T ≥ t1|T ≥ t0)P(T = t0)
≈ # uninfected at ti+1
# uninfected at ti× · · · # uninfected at t1
# uninfected at t0
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Biostatistics?
hypothetical example: breastfeeding
time 0 t1 t2 t3 · · ·# uninfected 100 90 70 50 · · ·# infected 0 10 10 10 · · ·# missing before ti 0 0 10 10 · · ·P(T ≥ ti |T ≥ ti−1) NA 90/100 70/(100-10) 50/(90-10-10) · · ·S(t) 1 1× .9 .9× 7/9 = .7 .7× 5/7 = .5 · · ·
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Biostatistics?
hypothetical example: formula feeding
time 0 t1 t2 t3 · · ·# uninfected 100 80 60 40 · · ·# infected 0 0 0 0 · · ·# missing before ti 0 20 20 20 · · ·P(T ≥ ti |T ≥ ti−1) NA 1.0 1.0 1.0 · · ·S(t) 1.0 1.0 1.0 1.0 · · ·
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Biostatistics?
hypothetical example: mixed feeding
time 0 t1 t2 t3 · · ·# uninfected 100 80 60 40 · · ·# infected 0 5 5 5 · · ·# missing before ti 0 15 15 15 · · ·P(T ≥ ti |T ≥ ti−1) NA 80/100 60/(100-20) 40/(80-20) · · ·S(t) 1.0 .8 .6 .4 · · ·
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Biostatistics?
Career as a Statistician
Website of the American Statistical Association(http://www.amstat.org/careers)
Government survey
Industry (drug development, quality control, market research)
Academia (statistical research, scientific research )
etc.
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Biostatistics?
Salary (Stat)
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Biostatistics?
Salary (Biostat)
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Biostatistics?
Salary (Industry)
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Apply to Grad Schools
APPLYING TO GRAD SCHOOLS
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Apply to Grad Schools
Before Applying...
Ask yourself
Do you have passion?
Do you have patience?
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Apply to Grad Schools
Which Schools to Apply?
Get rankings (usnews, www.phds.org, etc.) (6= difficulty of getting in)
Is funding available to all students (including master’s students)?
Proportions of PhD students successfully completing the program
Average years of completion.
Careers after graduate schools
Possible to change from a master’s program to a PhD program?
Male vs. Female, American vs Intl’ Students, Class size, etc.
culture, weather, etc.
Visit campus if you can (ask graduate programs)
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Apply to Grad Schools
What does an admission committee want to know aboutyou?
You know what you are going to do. ( = Strong Interests)Classes (stat)Research Experience in Statistics and Related FieldsConsulting ExperienceStatement of Purpose
You can do it. ( = High Potentials)GPALetters of RecommendationPublicationsResearch Experience in Other FieldsClasses in Math and ScienceGRE, etc.
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Apply to Grad Schools
What does an admission committee want to know aboutyou?
You know what you are going to do. ( = Strong Interests)
Classes (stat)Research Experience in Statistics and Related FieldsConsulting ExperienceStatement of Purpose
You can do it. ( = High Potentials)GPALetters of RecommendationPublicationsResearch Experience in Other FieldsClasses in Math and ScienceGRE, etc.
Takumi Saegusa (UW Biostat) Biostat PhD April 17 2013 23 / 35
Apply to Grad Schools
What does an admission committee want to know aboutyou?
You know what you are going to do. ( = Strong Interests)Classes (stat)Research Experience in Statistics and Related FieldsConsulting ExperienceStatement of Purpose
You can do it. ( = High Potentials)GPALetters of RecommendationPublicationsResearch Experience in Other FieldsClasses in Math and ScienceGRE, etc.
Takumi Saegusa (UW Biostat) Biostat PhD April 17 2013 23 / 35
Apply to Grad Schools
What does an admission committee want to know aboutyou?
You know what you are going to do. ( = Strong Interests)Classes (stat)Research Experience in Statistics and Related FieldsConsulting ExperienceStatement of Purpose
You can do it. ( = High Potentials)
GPALetters of RecommendationPublicationsResearch Experience in Other FieldsClasses in Math and ScienceGRE, etc.
Takumi Saegusa (UW Biostat) Biostat PhD April 17 2013 23 / 35
Apply to Grad Schools
What does an admission committee want to know aboutyou?
You know what you are going to do. ( = Strong Interests)Classes (stat)Research Experience in Statistics and Related FieldsConsulting ExperienceStatement of Purpose
You can do it. ( = High Potentials)GPALetters of RecommendationPublicationsResearch Experience in Other FieldsClasses in Math and ScienceGRE, etc.
Takumi Saegusa (UW Biostat) Biostat PhD April 17 2013 23 / 35
Apply to Grad Schools
What does an admission committee want to know aboutyou?
You know what you are going to do. ( = Strong Interests)Classes (stat)Research Experience in Statistics and Related FieldsConsulting ExperienceStatement of Purpose
You can do it. ( = High Potentials)GPALetters of RecommendationPublicationsResearch Experience in Other FieldsClasses in Math and ScienceGRE, etc.
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Apply to Grad Schools
Classes
GET GOOD GRADES.
Of course, all applicants take probability and statistics classes.
Analysis (Advanced Calculus) and Linear Algebra are required foradmission.
Taking graduate level Real Analysis and Probability are plus (youneed to learn it by yourself anyway).
Take computer science class to show your programming skills (in C,C++, etc., not in commercial statistical softwares).
Take science classes where you want to apply statistics and show howserious you are about applications.
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Apply to Grad Schools
Classes
GET GOOD GRADES.
Of course, all applicants take probability and statistics classes.
Analysis (Advanced Calculus) and Linear Algebra are required foradmission.
Taking graduate level Real Analysis and Probability are plus (youneed to learn it by yourself anyway).
Take computer science class to show your programming skills (in C,C++, etc., not in commercial statistical softwares).
Take science classes where you want to apply statistics and show howserious you are about applications.
Takumi Saegusa (UW Biostat) Biostat PhD April 17 2013 25 / 35
Apply to Grad Schools
Classes
GET GOOD GRADES.
Of course, all applicants take probability and statistics classes.
Analysis (Advanced Calculus) and Linear Algebra are required foradmission.
Taking graduate level Real Analysis and Probability are plus (youneed to learn it by yourself anyway).
Take computer science class to show your programming skills (in C,C++, etc., not in commercial statistical softwares).
Take science classes where you want to apply statistics and show howserious you are about applications.
Takumi Saegusa (UW Biostat) Biostat PhD April 17 2013 25 / 35
Apply to Grad Schools
Research Experience
Research Experience provides
the evidence of your strong interests
letters from supervisors verify your competency
Various ways to obtain research experience:
Participate in the REU (strongly recommended).
Google “Summer Institute Biostatistics”, “Research Experience forUndergraduate Statistics” etc.Find one for students where your expense will be covered.
Seek an opportunity on campus where statistical analysis would be ofhelp (computational biology lab, clinical and epidemiologcal research,research in sociology, economics, etc.)
Set up consulting services on campus.
Independent study with faculty.
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Apply to Grad Schools
Statement of Purpose
Can you explain how your interest in (bio)statistics has been shapedin a UNIQUE (=not superficial) and DETAILED way?
Can you show how serious you are about (bio)statistics or the field towhich you want to apply statistical methods with EVIDENCE?
Can you briefly write about your potential to do research withEVIDENCE?
Can you list some research directions you want to pursue in aCOHERENT way to the above?
Can you convince an admission committee that you have STRONGINTERESTS and HIGH POTENTIAL?
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Apply to Grad Schools
Biostatistics vs. Statistics
Biostatistics
Admit more students
More funding available throughresearch assistantship
Educational emphases onmethods and applications(scientific relevance moreemphasized)
More job opportunities inbiology-related fields
Background in Biology,Medicine, Math, CS, etc.
Statistics
Selective in admission
Limited funding throughteaching assistantship (teachingexperience)
Educational emphases on theory(not always) and methods(mathematical rigor moreemphasized)
Job opportunities in finance,engineering etc.
Background in Math and CS
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Apply to Grad Schools
References
Ask other alumni (Jimmy Doi, strongly recommended, several ppt filesfound at http://statweb.calpoly.edu/jdoi/web/research/index.htm).
Go online to find CV’s of the first or second year grad students andfind out their strengths you can learn to get.
Find books on how to apply to graduate schoolsNote: Most tips might be appropriate for other majors (biology, CS,etc.)
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Survival Guide
SURVIVAL GUIDE
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Survival Guide
The advice
Find a role model among students.
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Survival Guide
Study
Slow understanding does not hurt, but lack of patience to getcomplete understanding does.
Math vs. Engineering
Math (less emphasized in general): Rigorously prove theorems withminimum conditions.Engineering: Explain what conditions are not likely to hold in practiceand what happens to your statistical procedures if conditions fails.Engineering: Explain your statistical procedure to non-statisticians in aconcise way and convince them of its usefulness.
Forming a study group is often very helpful (take an initiative to formone).
Have fun!
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Survival Guide
Advisor
Choice of a thesis advisor is the most important than grades, your school,etc.
How successful their students are (Mathematical Genealogy Project orCV’s)
Publication records
Rumor from senior students
Get to know your potential advisors (through classes, departmentalevents, etc.)
Do readings with several potential advisors.
Personality match matters more because your interests change to bemore sophisticated...
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Survival Guide
Research
Very different from studying
Discontinuous progress = long time of getting nothing
Hot topics: severe competitions vs. job opportunities
Many projects vs. one deep research question
Different focus: mathematical skills, computational skills, deepunderstanding of applications, etc.
Take advantage of RA to do something different from your thesis
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Survival Guide
GOOD LUCK!
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