Iowa Cancer Incidence Data
VitalWeb Standard
Online Help




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Table of Contents


  1. Introduction

    Quick Guide to Using VitalWeb Standard
    Multiple Windows
  2. Table Settings

    Main Statistic
    Table Axes (Rows and Columns)
    Statistic / Axis Conflicts
  3. Data Variables

    Categorical Variables
    Range Variables
    Statistic / Variable Conflicts
    Other Settings
  4. Chart Settings

    Bar Chart Coloring
    Bar Chart Layout
    Line Chart Settings
    More Line Chart Settings
    Pie Chart Coloring
    Pie Chart Layout
    Tabular Charts / Chart Links
  5. Map Settings

    Map Coloring
    Map Layout
    Map Color Palettes
  6. Producing and Using Results

    Getting Results
    Viewing Results
    Printing Results
    Saving Results
  7. Other Information

    Glossary
    County Groupings
    95% Poisson Confidence Limits
    Age Adjustment Standards
    Statistical Methods
    Confidence Intervals
    Data Sources and Limitations
    Links to Related Resources
    Whom to Contact
    Legal Information



Quick Guide to Using VitalWeb Standard


Start Button First, select settings from within the Main Window:
Next, whenever you are ready:
After you have made output:


Multiple Windows


Screenshot: Multiple Windows

VitalWeb Standard uses multiple browser windows. Main Window ("command center") has the majority of settings and action buttons.

Map Settings Window customizes all map settings.

Other Settings Window: Help Window is what you are currently viewing.

Results Window displays any output maps or tables. Chart Setting Windows modify bar, line, and pie chart settings.


Main Statistic


Main Statistic - The basic numerical result in the output.

Main statistics include: Cancer Cases | Cancer Incidence Rate | Age-Adjusted Incidence Rate | Standardized Morbidity Ratio

Selecting - Click on desired setting, such as Cancer Cases.

 



Table Axes (Rows and Columns)


Year 0-1920-3940-5960+
1990 1,032 302 545 79
1991 1,134 317 555 88
1992 1,236 348 602 86


Example Table: Year Rows - Age Columns




Selecting - Click on desired setting, such as "Age" or "Race".


Statistic / Axis Conflicts


No Left Turn Sign If there is a conflict between statistic, rows, or columns:
Examples of conflicting settings (mismatches) include:
To correct a conflict, select a different Main Statistic, Row Variable, or Column Variable.


Selecting Data Variables


Data variables include - age, cancer diagnosis, county of residence, race, stage, year.

Example selector for data variable:  



Change Groups


Practice for selecting data variable:
  1. Select one value - Click on "Under 1".
  2. Add one value to selection - CTL-Click on "5 to 14".
  3. Delete one value from selection - CTL-Click on "Under 1".
  4. Select several values - Hold down mouse, drag over several.
  5. Select all values - Click on "All Ages".
  6. Change groups - Click on "Change Groups" at bottom.

Note: Can only "Change Groups" for "range variables", such as age or year.
Note: "CTL-Click" means: While holding down control key, click mouse.




Appearance of Data Selector for Geographic Areas:



 
Select areas - move from left to right

Unselect areas - move from right to left





To select geographic areas (in actual interface only):
  1. Highlight unselected area - Click on "Armstrong".
  2. Move area to "selected" column - Click on green arrow.

To unselect geographic areas (in actual interface only):
  1. Highlight selected area - Click on "Mills".
  2. Move area to "unselected" column - Click on red arrow.

Notes on geographic selection:


Selecting Data Variable Groupings


Certain data variables allow different "groupings".
For example, 5-year or 10-year age groups.


To change the grouping:






 


Example data grouping popup



Statistic / Variable Conflicts


No Left Turn Sign Sometimes, a conflict exists between a variable and a population-based rate. Vitalnet automatically prevents this from producing misleading output.
 
This is best shown with an example: Suppose there are 408,000 births, and the population is 12,000,000 females. Thus, the birth rate is 34 births per 1,000 females (408,000 / 12,000,000).
 
Now, suppose we try limiting the analysis to women with 12 years education. We know there are 108,000 births to such women. The result would seem to be 9 births per 1,000 such women (108,000/ 12,000,000). But of course this is totally wrong, because the denominator is not adjusted. And we don't have the population denominator data for women with 12 years education, so there is no easy solution.
 
To resolve this problem, when Vitalnet makes a rate calculation, it automatically prevents spurious results from being produced, by automatically adding all categories to demographic variables that are not included in the population data set.
 
So, for example, if you try to calculate a birth rate for women with 12 years of education, Vitalnet simply ignores the limitation to 12 years of education. Instead, it includes all levels of education, so the numerator and denominator match up. And it correctly reports that all levels of education were analyzed.
 
In contrast, if you try to calcuate a cesarean rate for women with 12 years of education, this does not require population data, only requires information on the births, so Vitalnet calculates the cesarean rate, limited to women with 12 years of education.


Other Settings


If you click on "Other Settings" in the Main Window, a separate "Other Settings Window" pops up. It lets you modify the following options:
 
Statistic Modifiers:
  - Age-Adjust Standard - Age-Adjustment Standard Population
  - SMR Standard - Standard for Calculating SMR
 
Secondary Statistics:
  - Cell Confidence Level - Confidence Level, such as 95%
  - Cell Suppression - Cell Suppression Level, such as 10
  - Table Percents - Row or Column Percents for Table
  - Trend Algorithm - Algorithm to use for Trend Analysis
  - Trend Confidence Level - Confidence Level, such as 95%
 
Miscellaneous Details:
  - Decimal Place Digits - Decimal Places, such as 2 for 5.99
  - HTML Output Font - Font for HTML Output, such as Arial
  - Spreadsheet Format - Spreadsheet Data Format, such as CSV
  - Tabular Chart - Tabular Chart Width, or Omit Chart
  - Unique ID - Unique ID on Maps and Charts

Example Selector, for One Setting:




Bar Chart Coloring


There are three settings for customizing Vitalnet bar chart colors:

  - The background color behind the chart.
  - The color palette to use for the bars.
  - The first color in the palette to use for the bars.

Below are shown the three settings, with examples for each:
 
 

Background Color for Chart (10 options)
 
Chart Image
White
 
  Chart Image
Grey 90
 
  Chart Image
Lemon Chiffon
 
  Chart Image
Light Blue
 

Color Palette for Bars (4 options)
 
Chart Image
Bright Colors
 
Chart Image
Subdued Colors
 
Chart Image
Bright + Subdued
 
Chart Image
Black + White
 

First Color in Palette to Use (10 options)
 
Chart Image
A Forward
 
Chart Image
D Reverse
 
Chart Image
E Forward
 
Chart Image
J Reverse
 



Bar Chart Layout


There are six ways to customize the layout of Vitalnet bar charts:
 
  - Bar height, and bar width.
  - Orientation (horizontal or vertical).
  - Stacking (works with either horizontal or vertical bars).
  - Grid lines may be added, or font size changed.
 
 

Bar Chart Height (9 options)
 
Chart Image
2 cm High
 
Chart Image
4 cm High
 

Width of Bars (8 options)
 
Chart Image
0.2 cm Wide
 
Chart Image
0.6 cm Wide
 

Vertical or Horizontal Bars
 
Chart Image
Vertical Bars
 
  Chart Image
Horizontal
 

Stacked Bars, or not Stacked
 
Chart Image
Stacked Bars
 
Chart Image
Not Stacked
 

Include or Omit Grid Lines
 
Chart Image
Include Grid
 
Chart Image
Omit Grid
 

Font Size for Chart Text (8 options)
 
Chart Image
10 pt Font
 
  Chart Image
14 pt Font
 



Line Chart Settings


There are eight ways to customize Vitalnet line charts, as shown on this and the next page.
 
 

Background Color for Chart (10 options)
 
Chart Image
Alice Blue
 
  Chart Image
Light Yellow
 

Include or Omit Data Point Symbols (2 options)
 
Chart Image
Include Symbols
 
  Chart Image
Omit Symbols
 

Radius for Chart Symbols (10 options)
 
Chart Image
1.0 mm Radius
 
  Chart Image
1.4 mm Radius
 

 
Line Chart Height - Vitalnet also allows you to set the chart height, eg 3.0 cm (9 height options).


More Line Chart Settings



Width of Lines (3 options)
 
Chart Image
Thin Lines
 
  Chart Image
Thick Lines
 

Include or Omit Grid Lines (2 options)
 
Chart Image
Include Grid
 
  Chart Image
Omit Grid
 

Colored Lines, or Black + White (2 options)
 
Chart Image
Colored Lines
 
  Chart Image
Black + White Lines
 

 
Font Size - Vitalnet also allows you to select font size, eg 9 pt (8 font size options).


Pie Chart Coloring


There are three settings for customizing Vitalnet pie chart coloring:

  - The background color behind the chart.
  - The color palette to use for the pie chart.
  - The first color in the palette to use (for slice #1).
 
 

Background Color for Chart (10 options)
 
Chart Image
Cornsilk Background
 
Chart Image
Grey Background
 
Chart Image
Light Cyan
 

Color Palette for Pie Chart (3 options)
 
Chart Image
Bright Colors
 
Chart Image
Subdued Colors
 
Chart Image
Mixed Colors
 

Slice #1 Color to Use (10 options)
 
Chart Image
Color A for #1
 
Chart Image
Color B for #1
 
Chart Image
Color C for #1
 



Pie Chart Layout


There are four settings for customizing Vitalnet pie chart layout, as shown below:
 
 

Slice #1 Clock Position (12 options)
 
Chart Image
Slice #1 at Noon
 
  Chart Image
Slice #1 at 3:00
 
  Chart Image
Slice #1 at 6:00
 

How to Label Pie Chart (9 options)
 
Chart Image
Line + Label
 
  Chart Image
Label Only
 
  Chart Image
Use Legend
 

How to Display Slice Percents (3 options)
 
Chart Image
Percent After Label
 
  Chart Image
Under Label
 
  Chart Image
Omit Percents
 

 
Pie Chart Radius - Vitalnet also allows you to select the pie chart size, eg 2.0 cm (9 options).


Tabular Charts / Chart Links


Tabular chart


A "tabular chart" is a convenient way of making comparisons.

The tabular chart is always made, unless turned off from the "Other Settings" menu. Also, you may specify the width of the columns within the chart.

Chart links: Note the links below the tabular chart. The links connect to additional graphical and data output formats. The example above links to bar chart, text, database, and spreadsheet formats.


Map Coloring



Color Combination for Map (36 options)
 
Map Image
Orange-Red
 
  Map Image
Grey
 
  Map Image
Red-Blue
 

Number of Map Colors (Ranges) (8 options)
 
Map Image
3 Colors
 
  Map Image
5 Colors
 
  Map Image
7 Colors
 

Equal Width, Equal Count, Jenks (3 options)
 
Map Image
Equal Count (Quantiles)
 
Map Image
Equal Interval
 
Map Image
Natural Breaks
 



Map Layout



Boundaries to Display (2 options)
 
Map Image
County Boundaries
 
  Map Image
HSR Boundaries
 
  Map Image
Border Counties
 

Cell Suppression (14 options)
 
Map Image
Suppression Off
 
  Map Image
Suppress < 10
 
  Map Image
Suppress < 30
 

 
PNG and PDF formats - Vitalnet always makes both PNG and PDF map output. Access the PDF version by clicking a link at the bottom of the web page with the PNG map. The PDF version is set to 8 1/2 x 11 inches.
 
Text Font for Map - There are 9 font options for displaying area labels:
 
[ Serif Normal ]     [ Sans-Serif Normal ]     [ Monospace Normal ]  
[ Serif Bold ]     [ Sans-Serif Bold ]     [ Monospace Bold ]  
[ Serif Italic ]     [ Sans-Serif Italic ]     [ Monospace Italic ]  
 
Time Trend Maps - Finally, Vitalnet can make (not shown here) a series of maps, one map for each selected year range. The map series is cycled within a special interface. The data ranges are the same for each map in the series, so you can directly compare the maps.


Map Color Palettes


1 2 3 4 5 6 7 8 9   Diverging Palette    BW   CB 
                                                        Brown-BlueGreen   - Y
                                                        Pink-Green   - Y
                                                        Purple-Green   - Y
                                                        Purple-Orange   Y Y
                                                        Red-Blue   - Y
                                                        Red-Grey   - -
                                                        Red-Yellow-Blue   - Y
                                                        Red-Yellow-Green   - -
                                                        Spectral   Y -
1 2 3 4 5 6 7 8 9   Sequential Palette    BW   CB 
                                                        Blue   Y Y
                                                        Blue-Green   Y Y
                                                        Blue-Purple   Y Y
                                                        Green-Blue   Y Y
                                                        Green   Y Y
                                                        Grey   Y Y
                                                        Orange   Y Y
                                                        Orange-Red   Y Y
                                                        Purple-Blue   Y Y
                                                        Purple-Blue-Green   Y Y
                                                        Purple-Red   Y Y
                                                        Purple   Y Y
                                                        Red-Purple   Y Y
                                                        Red   Y Y
                                                        Yellow-Green   Y Y
                                                        Yellow-Green-Blue   Y Y
                                                        Yellow-Orange-Brown   Y Y
                                                        Yellow-Orange-Red   Y Y


BW - OK for black and white photocopying?
CB - OK for people with red-green color blindness?
All palettes are suitable for desktop color printing.

References and research used to help design Vitalnet palettes: *** LW Pickle, M Mungiole, GK Jones, AA White, "Atlas of United States Mortality", National Center for Health Statistics, 1997. *** CA Brewer, "Color Use Guidelines for Mapping and Visualization", in "Visualization in Modern Cartography", Elsevier, 1994. *** ColorBrewer web site displays tested color palettes.


Getting Results


Go Sign To produce results:

1. Click on button - Click on "Make Map" or "Make Table". The program sends the query to the server.

2. View Results Window - Output will display in separate window. It takes a few seconds, depending on the analysis, the data set, and how much data.

3. Conflicts prevented - The program does not permit an invalid request. If a problem, such as row / column mismatch, you will be prompted to correct it before submitting request.


Viewing Results


Binoculars After you click "Make Map" or "Make Table", a separate "Results Window" appears.
 
To view results:
 
1. Scroll through the results - Use scroll bar, PgUp, PgDn, etc.
2. Print or Save results - Sends results to printer or disk.
3. Click on footnote links - Displays or downloads charts and data files.
 
Note: If viewing a map, pointing to a map area (use your mouse to position the cursor over a map area) displays the name of the area.
 
Note: Output forms a queue. In other words, new output replaces old output in the Results Window. Therefore, to review previous output, simply click the browser "Back" button in the Results Window.

Returning to Main Menu - To carry out another analysis:
  - Click on the Main Window, OR
  - Minimize the Results Windows.

If graphics do not display in the output, try refreshing the browser.


Printing Results


Printer To print results from your browser, use one of the following methods:
 
  - Press CTL-P - Hold down Control key, and press 'P' key.
  - Use Browser Icon - Click on Print Icon (if available).
  - Use Browser Menu - Select "File / Print" (if menu available).
 
If output table is too wide or long, here are two ways to make it fit:
 
  - Use fewer rows or columns. Also makes it easier to understand.
  - Change browser font size. Typical command is: View / Text Size.
 
How to print from a spreadsheet or word processor:
 
1. Click on the appropriate link in output footnotes.
2. Download and import the data file.
  - CSV / TSV / DIF for spreadsheet, such as Excel or StarOffice.
  - ASCII for word processor, such as Word or WordPerfect.
3. Format and print from within your spreadsheet or word processor.


Saving Results


File Cabinet To save results displayed in your browser, do one of the following:
 
  - Press CTL-S - Hold down Control key, and press 'S' key.
  - Use Browser Menu - Select "File / Save" (or equivalent).
 
To save an alternate data format, click on a footnote link:
 
  - ASCII text - For importing into word processing software.
  - CSV/TSV/DIF format - For importing into spreadsheet software.
  - dBASE III - For database, GIS, mapping, statistical software.
 
To save a map as an image file, minus any surrounding text:
 
  1. Position the cursor over the map, using your mouse.
  2. Press the right mouse button to bring up a popup menu.
  3. Select the "Save" option from the popup menu.
  4. Specify the directory (folder) to save the file.
 
Here are some suggestions on naming files:
 
  - Memorable - Select a name that will remind you of the content.
  - Organized - Organize files into project directories (folders).
  - Linkable - Use the unique ID for data files, such as "112jdhkm.dbf".


Glossary


 
Age-adjusted death rate - Deaths per 100,000 population, adjusted to a standard population (such as US 1940 or US 2000), by the direct method. Age-adjusted rates are often better for making comparisons than unadjusted rates, because they adjust for differences in age distribution between populations. An age-adjusted rate is a summary synthetic measure. Besides calculating overall age-adjusted rates, it is also recommended to compare age-specific rates.
 
Age-adjustment standard - A standard population for calculating an age-adjusted death rate. The 1940 and 2000 US Census population are the most common standards.
 
Area set - One or more areas combined.
 
ASCII file - A text file, with only alphabetical, numerical, and punctuation characters, like you would see in normal text. Vitalnet can produce output in ASCII format.
 
CDC - Centers for Disease Control and Prevention. US federal health agency.
 
Cell - A space for a single numerical result in a table, at a row-column intersection.
 
Cell suppression - An asterisk "*" is placed in cells with fewer deaths than a limit set by the user. Row / column totals with exactly one suppressed cell in the row / column are also suppressed. If more than one cell in the row / column is suppressed, the row / column total is displayed.
 
Columns - Vertical groupings of data in a Vitalnet table, such as a column for each race group.
 
Confidence interval (confidence limits) - A range of values within which the true value of a variable is thought to lie, with a specified level of confidence. For a result of 23.5, a confidence interval might be (23.1-23.9). The smaller the interval, the more reliable the result. If the 95% confidence intervals do not overlap, there is probably a statistically significant difference. Vitalnet uses several methods to calculate confidence intervals. The output table documents which method was used.
 
Confidence level - The likelihood that the true value of a variable is within a confidence interval. For example, for confidence intervals at the 95% level, we are statistically 95% certain that the actual value of the variable is within the interval.
 
CSV format - Comma-separated-value format. CSV files are readily imported into spreadsheet software. Each output item is separated by a comma from surrounding items, and each output text item is surrounded by "double quotes". A comma-separated-value file has "csv" extension. Similar to TSV format.
 
Data mining - Finding unexpected relationships in a data set, for further study. Similar to exploratory data analysis. Vitalnet is excellent at data mining. Of course, keep in mind that the more you look, the more unusual events you will find, just by chance.
 
Data warehouse - Software system, such as Vitalnet, making large complex databases readily available for querying and analysis.
 
dBASE III format - A widely used file format originally for the database software of the same name. Files in dBASE III format may be readily imported into almost any data analysis, graphing, mapping, or other presentation software. Uses dbf extension. Suppressed cells are represented as the number "-1".
 
DIF format - Data interchange format. DIF files are readily imported into spreadsheet software. The DIF format is too complex to explain in this glossary. Has "dif" extension.
 
Denominator - The number on the bottom of a fraction. Population data are often referred to as "denominator data", as they are used as denominators to calculate population-based rates.
 
Export - Produce output that can be read into other computer programs. Vitalnet produces ASCII text (txt), comma-separated-value (csv), HTML (htm), and dBASE III (dbf) files for export.
 
Filter variable - A variable solely used to filter which records are included in the output. For example, for a single table with race rows and sex columns, age is a filter variable.
 
Footer - Last part of a Vitalnet table. Lists less important details of the analysis, such as the date produced, and data sources. Also contains a unique ID to assist in keeping track of analyses.
 
Header - First part of a Vitalnet table. Lists key analysis parameters, such as years analyzed.
 
Import - Read information into a computer program. ASCII text, CSV, TSV, DIF, HTML, and dBASE III files from Vitalnet are easily imported into word processing, spreadsheet, data analysis, mapping, graphing, and other presentation software programs.
 
Least-squares - A standard method for fitting the best straight line to a set of points. Produces a Y-intercept and a slope defining the least-squares line.
 
Multiple age groups - One age group for each table row (or column). Example: 0-19, 20-59, 60-99+.
 
Natural Breaks - Method for determining map ranges. Minimizes "squared deviations from class means".
 
NCHS - National Center for Health Statistics. US health statistics agency. Part of the CDC.
 
Population - The number of people living in an area.
 
Rows - Horizontal lines in a Vitalnet table, such as a row for each race group.
 
Row sort settings - Vitalnet rows may be sorted in ascending or descending order.
 
Set - A combination of one or more things. For example, several areas may be combined into an area set.
 
Single age group - Only one age group (30-49, for example) is selected. A single age group is used for tables that do not have age columns or age rows.
 
Standardized mortality ratio (SMR) - The ratio of the expected number of deaths to the observed number of deaths. The expected number of deaths is derived by applying a standard set of rates (usually state or national rates) to a population. SMRs help assess whether the mortality in a population is higher than expected.
 
Statistic (Main Statistic) - The basic type of numerical result displayed in a table, chart, or map. For example, birth rate, death rate, population, pregnancy rate, etc.
 
Table - A set of results produced by Vitalnet. A table has several parts:
 
  1. Header - lists basic analysis settings
  2. Data section - numerical results
  3. Horizontal bar graphs - graphical representation of the data
  4. Footer - lists other analysis settings
 
Tabular chart - A section of a Vitalnet table. Gives an scaleable graphical representation of the data. May be omitted from the output table.
 
TSV format - Tab-separated-value format. TSV files are readily imported into spreadsheet software. Each output item is separated by a tab from surrounding items, and each output text item is surrounded by "double quotes". A tab-separated-value file has "tsv" extension. Similar to CSV format.
 
Unix - A popular set of computer operating systems. Vitalnet can run on Unix.
 
Unknown Values - Unknowns are automatically inserted into a Vitalnet table. For example, a separate row (or column) for unknown race. The rate is assigned as zero for an unknown category, since there is no population denominator to use. Some fields, such as sex for certain data sets, are never unknown, so unknowns are left off the table. When, such as for age-adjusted rates, the unknown variable (age) is different from the rows or columns, the number of unknowns for age is shown below the table.
 
Windows - Microsoft PC operating systems. Vitalnet runs under any version of Windows.
 
World Wide Web (WWW) - A widely used part of the internet that may be easily accessed with a web browser. Vitalnet runs on the WWW.


County Groupings


Region 1: Boone, Calhoun, Carroll, Dallas, Greene, Grundy, Hamilton, Hardin, Jasper, Marshall, Polk, Poweshiek, Story, Tama, Warren, Webster
 
Region 2: Allamakee, Bremer, Butler, Cerro Gordo, Chickasaw, Emmet, Fayette, Floyd, Franklin, Hancock, Howard, Humboldt, Kossuth, Mitchell, Winnebago, Winneshiek, Worth, Wright
 
Region 3: Buena Vista, Cherokee, Clay, Crawford, Dickinson, Ida, Lyon, Monona, O=Brien, Osceola, Palo Alto, Plymouth, Pocahontas, Sac, Sioux, Woodbury
 
Region 4: Adair, Adams, Audubon, Cass, Clarke, Decatur, Fremont, Guthrie, Harrison, Madison, Mills, Montgomery, Page, Pottawattamie, Ringgold, Shelby, Taylor, Union
 
Region 5: Appanoose, Davis, Des Moines, Henry, Jefferson, Keokuk, Lee, Louisa, Lucas, Mahaska, Marion, Monroe, Muscatine, Van Buren, Wapello, Washington, Wayne
 
Region 6: Benton, Black Hawk, Buchanan, Cedar, Clayton, Clinton, Delaware, Dubuque, Iowa, Jackson, Johnson, Jones, Linn, Scott


Age Adjustment Standards


Age group 1940 US 1970 US 2000 US
0 to 0 15,343 17,151 13,818
1 to 4 64,718 67,265 55,317
5 to 9 81,147 98,204 72,533
10 to 14 89,208 102,304 73,032
15 to 19 93,670 93,845 72,169
20 to 24 88,007 80,561 66,478
25 to 29 84,277 66,320 64,529
30 to 34 77,789 56,249 71,044
35 to 39 72,495 54,656 80,762
40 to 44 66,742 58,958 81,851
45 to 49 62,697 59,622 72,118
50 to 54 55,114 54,643 62,716
55 to 59 44,383 49,077 48,454
60 to 64 35,911 42,403 38,793
65 to 69 28,911 34,406 34,264
70 to 74 19,515 26,789 31,773
75 to 79 11,422 18,871 26,999
80 to 84 5,881 11,241 17,842
85 to 99+ 2,770 7,435 15,508
Total 1,000,000 1,000,000 1,000,000



Statistical Methods


The "Main Statistic" (numerical outcome) is the basic type of number in a Vitalnet table. It is best understood by looking at the examples below.
 
Cases - The number of cancer cases.
 
Incidence Rate - Cases per 100,000 population. This rate may be used to compare the burden of disease between different groups.
 
Age-Adjusted Rate - The number of cases per 100,000 population, adjusted to a standard population (such as US 1940), by the direct method. Age-adjusted rates are often better for making comparisons than crude rates, because they adjust for differences in age distribution between populations. An age-adjusted rate is a single summary measure. Be aware that it may mask trends detectable by examining age-specific rates. Age-adjusted rates are synthetic rates that are only useful in comparison with other age-adjusted rates. Age-adjusted rates are used to compare one area or population to another because age distribution is controlled for in the calculations. Age-adjusted rates are not typically calculated for individual age ranges, such as 40-49, and Vitalnet does not do so.
 
Standardized Morbidity Ratio (SMR) - The ratio of the number of observed cases to the number that were expected. Also called indirect adjustment. An SMR greater than 1 indicates more events were observed than expected. The number expected is derived by applying age-specific standard rates for a general population to the population in the area under study. The standard rates can include all races, or only the races being studied in the smaller area (race-specific). Similarly, the standard rates can include both male and female, or only the sex being studied in the smaller area (sex-specific). A standardized morbidity ratio is a single summary measure. It may mask trends detectable by examining age-specific rates. Standardized morbidity ratios are not usually calculated for individual age ranges, such as 40-49, and Vitalnet does not calculate such rates.
 
Age-Adjusted Rate Methodology - 1) Determine age-specific rates in the Study population. (Set age-specific rate to zero if age-specific population is zero.) 2) Multiply age-specific rates by Standard age-specific populations, such as 1940 US. 3) Sum the results from the previous step. 4) Divide the sum by the total size of the Standard population.
 
SMR Methodology - 1) Determine the age-specific incidence rate for each age group in the Standard (State) population. The age-specific rates may be based on all races combined, or just on the races that are selected (race-specific). 2) For each age group, multiply the age-specific rate by the number of people in that group in the Study population. 3) Sum the results from the previous step. This is the expected number of cases. 4) Divide the actual number of cases observed by the number expected (SMR = observed / expected). For example, if 10 cases were expected in a county (based on the State rate), and 20 occurred, the SMR is 2.


Confidence Intervals


 
Definition - A "confidence interval" is a range of values within which the true value of a variable is thought to lie, at a certain "confidence level", such as 95%. A larger percentage (such as 99%) is more stringent than a smaller percentage (such as 80%). Use 95% if you are unsure.
 
Interpretation - The smaller the interval, the more reliable the result. Two results that overlap at the 95% level are less likely to be significantly different than results which don't overlap.
 
Methods - The method Vitalnet uses to calculate confidence intervals depends on the context. The method is listed in the footnotes to the table.
 
Z * Rate / Sqrt (Events) - This method is recommended by the NCHS. Technical Appendix of the Vital Statistics of the United States, Vol II, Mortality, Part A
 
Rothman and Boice - This method is for SMRs. Rothman KJ and Boice JD (1979): Epidemiologic analysis with a programmable calculator. NIH Publication No. 79-1649, Washington, DC: U.S Department of Health.
 
Poisson distribution - This method is valid if events are relatively rare, which usually applies to health events. Scientific Tables, Diem and Lentner (ed), Giegy, 1970, page 189.


95% Poisson Confidence Limits


Events Lo Factor Hi Factor Events Lo Factor Hi Factor Events Lo Factor Hi Factor
1 0.025318 5.571647 70 0.779549 1.263440 4,000 0.969250 1.031230
2 0.121104 3.612346 80 0.792938 1.244587 5,000 0.972473 1.027911
3 0.206224 2.922426 90 0.804118 1.229170 6,000 0.974857 1.025464
4 0.272466 2.560398 100 0.813640 1.216268 7,000 0.976711 1.023564
5 0.324697 2.333667 200 0.866209 1.143395 8,000 0.978207 1.022034
6 0.366982 2.176580 300 0.890041 1.116362 9,000 0.979446 1.020767
7 0.402052 2.060382 400 0.904401 1.100401 10,000 0.980496 1.019696
8 0.431729 1.970399 500 0.914267 1.089575 20,000 0.986189 1.013907
9 0.457263 1.898312 600 0.921584 1.081617 30,000 0.988716 1.011348
10 0.479539 1.839036 700 0.927291 1.075453 40,000 0.990224 1.009824
20 0.610826 1.544419 800 0.931904 1.070497 50,000 0.991254 1.008785
30 0.674696 1.427562 900 0.935734 1.066400 60,000 0.992014 1.008018
40 0.714415 1.361716 1,000 0.938980 1.062941 70,000 0.992606 1.007422
50 0.742219 1.318376 2,000 0.956653 1.044307 80,000 0.993082 1.006942
60 0.763105 1.287198 3,000 0.964536 1.036105 90,000 0.993477 1.006544




Data Sources and Limitations


VitalWeb Standard uses data from authoritative sources.

Cancer incidence data - All cancer incidence data were provided by the NCI SEER Program - (seer.cancer.gov).


Links to Related Resources


Internet resources related to Cancer Incidence Data:


Whom to Contact


For additional assistance with analyzing and interpreting the data, contact:

Legal Information


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Documentation produced: "Jul 18 2017" - Contact EHDP