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Careers in Statistics. The Role of a Biostatistician Presentation at Central College Pella, Iowa. What comes to mind when you hear the word “statistics”?. Sports statistics? Vital health statistics? Just numbers?. Leading causes of death in the U.S.

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Careers in statistics

Careers in Statistics

The Role of a Biostatistician

Presentation at Central College

Pella, Iowa


What comes to mind when you hear the word statistics

What comes to mind when you hear the word “statistics”?

  • Sports statistics?

  • Vital health statistics?

  • Just numbers?


Leading causes of death in the u s

Leading causes of death in the U.S.


Cancer death rates for men us 1930 2000

Cancer Death Rates*, for Men, US, 1930-2000

Rate Per 100,000

Lung

Stomach

Prostate

Colon & rectum

Pancreas

Leukemia

Liver


Cancer death rates for women us 1930 2000

Cancer Death Rates*, for Women, US, 1930-2000

Uterus

Lung

Breast

Colon & rectum

Stomach

Ovary

Pancreas


Tobacco use in the us 1900 2000

Tobacco Use in the US, 1900-2000

Per capita cigarette consumption

Male lung cancer death rate

Female lung cancer death rate


Trends in overweight prevalence adults 18 and older us 1992 2002

Less than 50%

50 to 55%

More than 55%

State did not participate in survey

Trends in Overweight* Prevalence (%), Adults 18 and Older, US, 1992-2002

1992

1995

2002

1998

*Body mass index of 25.0 kg/m2or greater

Source: Behavioral Risk Factor Surveillance System, CD-ROM (1984-1995, 1998) and Public Use Data Tape (2002), National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, 1997, 2000, 2003.


Discipline of statistics

Discipline of Statistics

  • The statistics presented here involve massive efforts to collect the data, followed by simple calculations.

  • We see differences, but are they meaningful? Could they have happened by chance?

  • If we see trends that we do not like, what can we do to effect change?


Discipline of statistics1

Discipline of Statistics

  • Numbers carry information, but we need numerical reasoning to make their meaning clear.

  • The discipline of statistics uses mathematical tools to quantify uncertainty and assign a likelihood that what we see could have happened by chance.

  • Biostatistics is just statistics applied in the health sciences.

  • Mathematics and math logic play critical roles.


Typical research questions

Typical Research Questions

  • We rely heavily on medications to treat diseases and medical conditions.

    • How do we know that they work (are efficacious) and are safe?

  • Heart disease is the #1 cause of death.

    • How can we assess if an intervention is effective in reducing a person’s risk?


Competing possible errors

Competing Possible Errors

  • Any research study has the possibility of making one of two types of errors:

    • Type I: Declaring a significant effect when in fact there is none.

    • Type II: Failing to find a significant difference when there is one.

  • In statistics, we use mathematical theory and modeling to find optimal decision rules and choose sample sizes which will reduce the likelihood of these errors to acceptable levels.


Example clinical trials

Example: Clinical Trials

  • One type of research design to address such questions is known as a clinical trial.

  • In a clinical trial, patients are randomly assigned to either the new drug/treatment or “standard care”.

  • When possible, both patients and doctors are blinded to the assignment.


Clinical trials

Clinical Trials

IHAST2 Trial

Intraoperative

Hypothermia for

Aneurysm Surgery Trial

Michael Todd MD, Bradley Hindman MD,

William Clarke PhD, James Torner PhD

University of Iowa

and the IHAST2 Investigators.

Supported by NIH RO1 NS38554


Ihast1

IHAST1

  • Hypothermia was first used in neurosurgery in 1955.

  • Based on research experience with animals, it was believed that cooling the body before neurosurgery would be protective against central nervous system (CNS) insults.

  • At present, at least 50% of current open neurovascular cases are cooled (Pemberton, 2003).

  • However, this was being done without a rigorous assessment of outcomes.


Ihast11

IHAST1

  • In 1999, U. of Iowa researchers published the results of a small pilot clinical trial on this*.

  • They randomly assigned 114 patients with and without acute aneurysmal subarachnoid hemorrhage (SAH) to either cooling or normal body temperature before surgery

    • Cooling = target body temperature of 33.5 C

    • Normal = body temperature 37C

Hindman, Todd, et al. Neurosurgery. 1999 Jan;44(1):23-32; discussion 32-3.


Ihast12

IHAST1

Outcome = Glasgow Outcome Score at Three Months


Ihast13

IHAST1

  • Is it beyond reasonable doubt that hypothermia is working?

  • SAH patients (n=52) : 71% vs. 57% =“good”

    • Looks like hypothermia is helping.

  • No SAH (n=62): 77% vs. 76% = “good”

    • Looks like little effect of hypothermia.


Ihast14

IHAST1

  • Answer:

    No - there is reasonable doubt.

  • Statistical methods were used to determine

    (1)These differences, given this sample size, could have reasonably occurred by chance .

    (2)It would need a randomized clinical trial of at least 900 patients to assure that we could detect a 10% improvement (from 65% to 75%) in the Glasgow outcome score at three months with 90% power.


Ihast2

IHAST2

  • The follow-up International, multi-center randomized clinical trial was funded by NIH (IHAST2).

  • 1000 SAH patients undergoing craniotomies for aneurysm clipping were randomized to either hypothermia or normal body temperature.

  • Primary outcome measure: Glasgow Outcome Score (GOS) at 3 months


Ihast2 glasgow outcome score

IHAST2: Glasgow outcome score

The previous 71%-57% difference has now shrunk to a 66%-63% difference


Ihast21

IHAST2

Now, is it beyond reasonable doubt that hypothermia is working?

  • This study had a large enough sample size to find a meaningful difference in “good” outcomes due to hypothermia (should it work) with high probability.*

    Beyond reasonable doubt, it simply does not work as believed.

* Many other outcomes were also tested. All consistently showed no benefit.


Missouri turkey hunting survey

Missouri Turkey Hunting Survey

  • The Missouri Department of Conservation is interested in turkey hunting success rates.

  • Can we obtain an estimate of the hunting success rate in every county on every day of the hunting season even if we don’t have a sample from that county?

    (small area estimation)


Missouri turkey hunting survey1

Missouri Turkey Hunting Survey


Missouri turkey hunting survey2

Missouri Turkey Hunting Survey


Missouri turkey hunting survey3

Missouri Turkey Hunting Survey


Missouri turkey hunting survey4

Missouri Turkey Hunting Survey


What do statisticians do

What do statisticians do?

  • Surveys

    • political surveys

    • National Health and Nutrition Examination Survey

  • Government Operations

    • Census Bureau

    • FDA

  • Scientific Research

    • Cancer trends

    • Survival probability

    • Genetics

  • Business and Industry

    • Pharmaceuticals

Source: http://www.amstat.org


Careers in statistics

Business

Economics, Engineering,

Marketing,

Computer Science

Physical

Sciences

Astronomy,

Chemistry, Physics

Areas where

STATISTICS

are used

Health &

Medicine

Genetics, Clinical Trials,

Epidemiology,

Pharmacology

Environment

Agriculture,

Ecology, Forestry,

Animal Populations

Government

Census, Law,

National Defense

Source: http://www.amstat.org


Roles of a biostatistician

Roles of a Biostatistician

  • Guardian of the science.

    • Help write the proposal to get this study funded.

    • Maintain an unbiased perspective.

    • Determine which data needed to be collected.

    • Determine what methods would be used.

    • Anticipate how proposed changes in the program would affect ability to make inferences and argue against them when needed.

    • Develop new methods when needed.


Roles of a biostatistician1

Roles of a Biostatistician

  • Keeper of the Data.

    • Work with different state and federal agencies to obtain data.

    • Check data for recognizable errors.

    • Merge data from different sources.

    • Maintain and secure the project database.

    • Work with others (e.g., national evaluators, statistical coordinating centers) to blend your data with other data.


Roles of a biostatistician2

Roles of a Biostatistician

  • Analytic Support

    • Investigate the data from many angles.

    • Assess assumptions of proposed models.

    • Fit statistical models.

    • Interpret results of the models for the research team.

    • Make sure that the investigators do not draw conclusions beyond what can be supported by the data.

  • Author (Write up results / provide graphics.)


  • What about salaries

    What About Salaries?

    • Annual (median) salary with 0-1.9 years of experience for

      MastersPhD

      -Statistician60,00083,000

      -Male Statistician56,50083,000

      -Female Statistician62,00083,000

      -Assistant Professor (4 year college) 53,000

      -Assistant Professor (Research)63,000

      -Pharmaceutical statistician73,00083,000

    Source: http://www.amstat.org


    Life as a graduate student

    Life as a Graduate Student

    • What do you do as a graduate student?

      • Classwork

      • Teaching assistants

      • Research assistants

      • Go to football games!


    Variety of scientific projects

    Variety of scientific projects

    As you can tell, people work on various different projects. The following are brief excerpts from some recent projects.


    Driving simulator nads

    Driving Simulator (NADS)

    A shared-use research facility operated by The University of Iowa, The NADS was created to conduct research which will help save lives, reduce the costs of vehicle crashes, and lead to better and safer vehicles, roadways, and drivers.

    http://www.nads-sc.uiowa.edu/


    Iowa cochlear implant center

    Iowa Cochlear Implant Center

    While normal hearing has increased significantly, implants still do not reproduce a high quality of music.

    Is it beneficial to have two cochlear implants for those who are profoundly deaf?


    Iowa bridge to employment study

    Iowa Bridge to Employment Study

    Mental Illness Group

    Mental Retardation Group

    • Purpose: To determine if special services provided to Iowans with disabilities would increase the likelihood of employment.


    Wise woman

    Wise Woman


    Careers in statistics

    Total Physicians

    Cancer Crude Rates

    50

    40

    < 10,000

    30

    10,000 - 20,000

    > 20,000

    Rate Per 100,000 Population

    MSA

    20

    State of Iowa

    10

    0

    1978-1983

    1984-1989

    1990-1995

    1996-2002

    Year

    http://www.public-health.uiowa.edu/FACTBOOK


    Holden comprehensive cancer center

    Holden Comprehensive Cancer Center

    Tumor growth curve estimates from a mixed linear models analysis.

    Group comparisons indicate differences between specific groups at the 5% level of significance.


    Careers in statistics

    Spatial statistics

    Radon concentrations measured in the basements of homes in Iowa.


    Thank you

    Thank you!

    Jake Oleson

    Central College

    class of 1997


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