BIOS601 Resources: Surveys & Measurement

[updated August 21, 2013]

Link to the Oceanography Data and R code to measure the mean height of the land and the mean depth of the ocean

Go to Material on Measurement.

Surveys -- Lecture Notes

(JH's) Notes, prepared for epidemiology students

Surveys -- Chapters from Bradford Hill's text

Collection of Statistics - Sampling

Collection of Statistics - Selection

Hill distinguishes

 a deliberately drawn sample  ...  from one where

 we have to accept whatever sample of observations may present itself

Collection of Statistics - Forms of Record and Inquiry
. Advice on the form of record upon which to ask questions and to record the answers
. The time to be concerned about the quality of this form of record...
"is not at the end of an investigation, but at its beginning."

How many hours a week do (medical) interns work/sleep?

(Web-based) Survey of students in McGill intro Epi and Biostat courses, 2001

The survey
The raw data (text file with | as delimiter )
SAS statements used to parse/process the raw data
Comma-separated (csv) file exported from SAS Can open in Excel, or read into R using
```
 read.table("606_607_data_csv.txt",header=T,sep=",") 
```

Examples of Stratified Samples:

Examples of Multi-Stage Samples:

Examples of Cluster Samples:

*** The Quebec Child and Adolescent Health and Social Survey:
design and methods of a cardiovascular risk factor survey for youth
.
*** Mortality before and after the 2003 invasion of Iraq [ Lancet. 2004] ;

See also:- Comment in: Lancet. 2004 Nov 20-26;364(9448):1831-5.
2005 Mar 26-Apr 1;365(9465):1133; author reply 1133-4. 2005 Mar 26-Apr 1;365(9465):1134-5.
.
*** Mortality after the 2003 invasion of Iraq:
a cross-sectional cluster sample survey.[Lancet. 2006]

The Oct 2006 Lancet podcast (mp3 file -- 5.1Mb) discusses the research article
documenting 650,000 excess deaths in Iraq since the 2003 conflict started.
The 1st half of interview is with the Lancet Editor, the 2nd with one of the investigators.

See also: Comment and author reply:- 2007 Jan 13;369(9556):101-5.]

Variance for Estimates from Cluster Samples: "Effective sample size"

Household Survey Example from Cochran's text

Other Examples of Surveys

*** Declining rate of folate insufficiency among adults following increased folic acid food fortification in Canada.
Sampling Events in Space and Time: Burn Injuries

article: *** scanned | *** by o.c.r. [smaller file, but several small o.c.r. errors!]

"What If? " -1- | -2-
A new survey of American men shocks the nation with what it didn't find
Newsweek 1993: Deals with scientific and non-scientific samples; MEASUREMENT;
measures of central tendency and variability.
Radon linked to more lung cancer deaths than previously thought. CBC 2012.

Cross-Canada Survey of Radon Concentrations in Homes - Final Report. Health Canada 2012.

On the height of the land and the depth of the ocean: Using sampling to estimate them

Oceanography Data

Further Comments / Caveats / Resources on Sampling and Measurement:

(1999) Assignment on sampling Sampling Frame | Recording sheets: page 1 | page 2 | page 3
"Bigger sample sizes won't fix these problems ..."
Bias and Variability ... being approximately correct and precisely wrong!
If Prob(selection) is proportional to quantity being measured -- Length-biased sampling
How come Gallup uses the same n=1000 in the U.S. and Canada?
Performance of Gallup Poll in U.S. Presidential Elections 1952-1988
Sample Size and Sex
A Big State needs a Big Sample
Standard Error for a Weighted Average of Stratum-specific Estimates
How long are words?
Using Random Number Table (from Armitage&Berry) See also M&M sections 3.2&3.3
Systematic Sampling: cf M&M Q 3.41 p264-265 Note on this technique (FDK Liddell)
Limits of memory in Surveys:
- Answering autobiographical questions: the impact of memory and inference on surveys.
- Citations of Bradburn's work
Effects of Responder Age and Cognition, and Question Framing, in Surveys
[work of B Knäuper, McGill Psychology department]
Readability Indices
- The SMOG Readability Formula
  Simple Measure Of Gobbledygook - interesting material by the originator of the index [NB: his Online Calculator is no longer functional]
  
  Online SMOG Calculator
  Calculate the SMOG index for a document/piece of text - Courtesy of NIACE (The National Institute of Adult Continuing Education), the leading non- governmental organisation for adult learning in England and Wales. Quicklink
- Fry Graph for Estimating Readability
  Fry Readability Formula (From Wikipedia)
- Flesch-Kincaid Readability Statistics in Microsoft Word
  Flesch-Kincaid Readability Test (Wikipedia)

Measurement -- Lecture Notes, etc

Notes & articles on Psychometrics for students in rehabilation sciences

Introduction to Measurement Statistics
Quantifying Reliability
Validity Statistics

Reproducibility / Validity of Drano Test

Statistical Methods for assessing agreement between 2 methods of clinical measurement
(re-typed version of) Bland and Altman, Lancet 1986; i: 307-310)

Statistical Methods for assessing agreement between 2 methods of clinical measurement
(original) Bland and Altman, Lancet 1986; i: 307-310)

Short note, "Validating scales and indexes", by same authors, BMJ 2002
Additional Notes/Resources for students in BIOS601

Effects of Errors in X and Y

Notes from Applied Linear Models course for biostatisticians/statisticians

Karl Pearson on why Galton got different parent-offspring correlations in heights
and he (KP) got a larger/common correlation with his own carefully collected data
Expected mean squares (EMS) in fixed, mixed and rando effects (anova) models.. cf p28+ pdf
Lecture Notes (from Measurement Course) on Measurement Statistics and Reliability
Expected Mean Squares: ANOVA Tables for various data structures pdf
Expected Mean Squares: Demos (Excel):
1-way, fixed effects
1-way, random effects
simple linear regression
Coverage of Variance Components in book by Armitage & Berry pdf
Weight Gain: how much is in the genes? Time/NEJM Data / R & WinBUGS code
Observer variation in measuring earlength BMJ Data/R/WinBUGS code
(Automated) Blood Pressure and Pulse (Heart Rate) Measurements
discarded by customers of Jean Coutu pharmacy
pdf .txt (Adobe Acrobat Optical Character Recogntion (OCR). caution: contains OCR errors)
Galton's data on Family Stature (heights) of parents and siblings raw data .csv file
The Heritability of Otitis Media: A Twin and Triplet Study JAMA article .csv file (Tall format)
Notes and Exercises on Variance Components, Bios602, Winter 2011 pdf
Random measurement error and regression dilution bias

article by J Hutcheon, A Chiolero and J Hanley BMJ 2010;340: 1402- 1406. Animation
(see also, at bottom of this page. "Animation (in R) of effects of errors in X on slope of Y on X")
Monitoring Cholesterol Levels: Measurement Error or True Change?

article by Glasziou, Irwig, et al. Ann Intern Med. 2008;148:656-661
Long term monitoring in patients receiving treatment to lower blood pressure: analysis of data from placebo controlled randomised controlled trial

article by Glasziou, Irwig, et al. BMJ. 2009 Apr 30;338:b1492. doi: 10.1136/bmj.b1492.

Quality of Handwriting

The truth about doctors' handwriting: a prospective study Berwick, BMJ, 1996
Handwriting Samples pdf

Computer code to simulate datasets with measurement error

Computer code to simulate datasets and look at sampling distribution of parameter estimates
temperatures measured with error - SAS

temperatures measured with error - R

Animation (in R) of effects of errors in X on slope of Y on X

R code for 'animation' package .R file
A completed animation .pdf file

An (undiscovered for almost 300 years) Bernoulli Error? or Not?

Questions from ch 3 of Moore & McCabe 3rd Edition

3.33, 3.34, 3.35, 3.36, 3.39, 3.41, 3.43, 3.44, 3.45, 3.46, 3.47, 3.48, 3.49, 3.50, 3.57, 3.72, 3.74, 3.79