‘10-’11Writing Questions and Hypotheses 6350 Lecture 3: Developing a Project with Hypotheses 1.Key Concepts: How a question is developed Proper Literature

‘10-’11 Writing Questions and Hypotheses

6350 Lecture 3: Developing a Project with

Hypotheses

1. Key Concepts: How a question is developedProper Literature Citations (test)Hypothesis Writing (test)Clinical Grading (e.g., staining; test)

Thought for the Day

“To him/her whose elastic and vigorous thought keeps pace with the sun, the day is a perpetual morning”

Henry David Thoreau

Student Research and the Research Question

The Most Important Aspect of Research (according to JP)

You want people to say: “What a neat idea!”

when you describe your project


It’s Tough to Ask a Good Question!


Dr. Paugh’s Example – The “Refresh Contacts” Study

• Solution toxicities observed clinically with multi-purpose solutions (MPSs)

• Carboxymethylcellulose (CMC):– Ubiquitous wood fiber; viscosifying agent in artificial

tears and CL lubricants

The Question: Can a pre-application drop of CMC

reduce solution toxicity?


Grade 3.5 SPK “worst sector” on a 0-4 Scale; Grade 14.5 on a 0 – 20 Total Scale


Dr. Paugh’s Example

What does the literature say?• Solution reactions exist:

– especially silicone-hydrogels & MPSs

• Evidence that CMC can neutralize MPS actives (i.e., PHMB)

• Vehige et al., Eye and CL, 2003: chemical availability of PHMB less in water and MPS when CMC present

• Also, bacterial survival rates greater when CMC added

binding

How Do We Reference the Literature?

(especially in this increasingly electronic age?)


Literature Citations• Uniform Requirements for Manuscripts

Submitted to Biomedical Journals– Used by many medical journals, including

OVS, IOVS, etc.

• International Committee of Medical Journal Editors (ICMJE); general medical journal editors who meet annually to develop uniform standards)

• Consider reference software such as EndNote


Citing Electronic Material: ICMJE*

How To: SCCO Library:1. Go to intranet, SCCO Library

2. Click on “How To”

3. Click on “ICMJE”

4. Go to specific chapter you need

*Patrias K. Citing medicine: the NLM style guide for authors, editors, and publishers [Internet]. 2nd ed. Wendling DL, technical editor. Bethesda (MD): National Library of Medicine (US); 2007 [updated 2009 Oct 21; cited Year Month Day]. Available from: http://www.nlm.nih.gov/citingmedicine


Citation-Journal (paper):

• Use Index Medicus abbreviations for the journal (e.g., Optom Vis Sci)

• List the first six authors followed by “et al.”

• Example:– Halpern SD, Ubel PA, Caplan AL. Solid-organ

transplantation in HIV-infected patients. N Engl J Med. 2002;347:284-7.


Citation-Book (paper):

• Personal Author:– Murray PR, Rosenthal KS, Kobayashi GS,

Pfaller MA. Medical microbiology. 4th ed. St. Louis:Mosby;2002. + page numbers!!!


Citation-CD-ROM (“electronic material”)

Anderson SC, Poulsen KB. Anderson’s electronic atlas of hematology [CD-ROM]. Philadelphia: Lippincott and Williams and Wilkins; 2002.

e.g.:

e.g.:


Citation-Internet Journal Article:

e.g.:


Citation-Homepage/Web Site

– Cancer-Pain.org [homepage on internet]. New York: Association of Cancer Online Resources, Inc.; c2000-01 [updated 2002 May 16; cited 2002 Jul 9]. Available from http://www.cancer-pain.org/.


Citation-SCCO Student Research Paper

– Williams R. Strabismus and its therapies [student research paper]. Fullerton (CA): Southern California College of Optometry; 1980.

– Note: could have a second author and faculty advisor as well


FINER TEST (for student research)

• F – feasible (adequate subjects, affordable?)

• I – interesting (to investigator & profession)

• N – novel (confirms or refutes prior work)

• E - ethical

• R – relevant? (to knowledge, clinical care?)

(i.e., the So What? Test)


Dr. Paugh’s Example (Refresh Contacts)

• Poll Contact Lens Staff-What do you think?• So What?• Clinical care:

– may corroborate in vitro findings– may develop a simple and cost effective solution

to a given problem– Pre-application drop lubricates the lens-eye

system-a benefit!

• Feasibility!



• Is there a difference between pre-instillation of a CMC vs. a non-CMC lubricant?– i.e., subjective?

• Dryness, comfort etc.

– i.e., objective?• Staining (overall and cumulative)• Bulbar injection• Limbal redness


REFINING AND DEFINING:IMPORTANT!!!!!!!!!

• Keep it small

• Define the population rigorously

• Focus on one thing - one relationship

• Define the end-point in terms of primary outcome variable(s) and secondary outcome variable(s)

• What exactly are you going to measure?


Dr. Paugh’s example

Population

• Experienced soft lens wearers– NB: ideal would be identified solution

responders– In reality, ANY soft lens wearers– > age 18 (expedited IRB review)– No torics

• Fit with lens material that is likely to demonstrate the problem- Ethics???


Dr. Paugh’s example, cont’d

Methods:

• Fit all subjects with one lens material

• All subjects disinfect with ReNu

• During one 4-week period, use ReNu lubricant as pre-application drop

• During 2nd 4-week period, use CMC lubricant as pre-application drop

• Responses: subjective & biomicroscopy


Variables – Definitions (textbook)

• Independent variable or Predictor variable– The variable that is held constant; HOWEVER, the

investigator controls it– A factor that is suspected to influence the outcome of

an analytic study (e.g., a CL lubricant, or drug treatment, etc.)

• Dependent variable or Outcome variable– Primary– Secondary– The response of interest (e.g., the development of

staining, cure of disease etc.)



• What is the independent / predictor variable?– e.g., disinfecting solution?– Lens material?– Length of wear?– Lubricant?

• What is the dependent / outcome variable?– e.g., comfort? staining? refractive error?


Research Questions: Summary

• “Ask a Good Question!!!”

• How?Discover an unanswered need:

• Why does this happen clinically? What is known about this?, etc. Literature review; speak with experts


Dr. Paugh’s Questions-Personal• How long does an ophthalmic solution last on the

ocular surface?• Can a novel, more convenient method be

developed to measure epithelial barrier function?• What are the factors that influence tear exchange

beneath contact lenses?• Does ed peri-ocular humidity improve non-

invasive tear parameters?• What is the in situ aqueous tear viscosity?


Dr. Paugh’s Questions-Student

• How much plus can be added to a rigid CL prior to optical distortion?

• What is the prevalence of MGD?

• Do warm compresses for MGD really provide benefit?

• Do neophyte, latent hyperopes accept more plus with rigid contact lenses?


Faculty to Contact:

• Drs. Sendrowski, Comer, Tong: Ocular Disease• Drs. Barnhardt, Cotter, Borsting, Chu:

– Pediatrics, VT, dyslexia, strabismus

• Drs Jim Bailey, Stark– Accommodation, VT, Visual Optics

• Drs. Edrington, Marsden, Lam et al.– Contact lenses, tear film, keratoconus

• Dr. Ridder: Contrast threshold, ERG, aberrations

• Dr. Paugh: Tears, CLs, dry eye

List in Your Hands!!!


GENERATING HYPOTHESES

• Specify the end-point carefully:– e.g., IOP, TBUT, BI to break, etc.

• What are you measuring exactly?– Is it best expressed as a mean?

• e.g., average score, average difference, average visual acuity, average IOP

– Is it best expressed as a proportion?• e.g., percentages, proportion with and without (a

condition), categories (disease, no disease)


HYPOTHESES: General

• Null is always “no difference”

• Alternative can be one-tailed or two-tailed

• What is of interest to you?

• What makes sense clinically?


NULL HYPOTHESIS• There is no difference between...

– ...Is not associated with...– ...Is not different...

• Symbols: mu for means pi for proportions

• Use equal sign =• E.g.:

– Ho: 1 = 2

– Ho: 1 = 2


ALTERNATIVE HYPOTHESIS

• One-tailed or two-tailed?

• Not equal, greater than, less than

• Symbols: (mu) for means

(pi) for proportions

• Use appropriate mathematical symbol for one-tailed or two-tailed ≠; >; <


Dr. Paugh’s CMC Example

• What exactly did we measure as the principal outcome measure?

• Is this expressed as a proportion or a mean?



• Should the alternative hypothesis be one-tailed or two-tailed?– Could SCL wearers have more or less staining

when using lubricants?

• Two-tailed makes it more difficult to demonstrate significance, but, more robust statistically

use 2-tailed approach if possible


Examples: Writing Hypotheses

• Null (no difference) Hypothesis:– E.g., There is no difference in the residence time, in

minutes, between product 1 and product 2

– Ho: 1 = 2

• Alternative Hypothesis:– There is a difference in residence time, in minutes,

between product 1 and product 2

– HA: 1 ≠ 2

• Two-tailed most robust (because covers all possible outcomes)

Documents

‘10-’11Writing Questions and Hypotheses 6350 Lecture 3: Developing a Project with Hypotheses 1.Key Concepts: How a question is developed Proper Literature