California Birth Data
VitalWeb Ajax
Online Help

Introduction

Quick Guide to Using VitalWeb Ajax

Multiple Windows
Basic Table Layout

Main Statistic

Table Axes (Rows and Columns)

Statistic / Axis Conflicts
Data Variables

Categorical Variables

Range Variables

Statistic / Variable Conflicts

Other Settings
Chart Settings

Bar Chart Coloring

Bar Chart Layout

Line Chart Settings #1

Line Chart Settings #2

Pie Chart Coloring

Pie Chart Layout

Tabular Charts / Chart Links
Map Settings

Map Coloring

Map Layout

Map Color Palettes
Producing and Using Results

Getting Results

Viewing Results

Printing Results

Saving Results

When Charts and Maps are Made
Other Information

Glossary

Race Categories

County Groupings

95% Poisson Confidence Limits

Statistical Methods

Confidence Intervals

Data Sources and Limitations

Links to Related Resources

Whom to Contact

Legal Information

Quick Guide to Using VitalWeb Ajax

First, select settings from within the Main Window:

• Main Statistic, for example "Births per 1,000 People"
• Rows and columns, for example year rows
• Values for data variables, for example race

Next, whenever you are ready:

• Click on "Make Table Now" or "Make Map" to submit your query.
• Results will appear in a separate "Results Window".
• Browse through your results.
• Print your results (if desired).
• Save your results (if desired).

After you have made output:

• Go back to the the Main Window.
• Modify settings as desired.
• Make another map or table.

Multiple Windows

VitalWeb Ajax uses multiple browser windows.

• It does not require full-screen windows.
• You can easily switch between browser windows.
• To switch to another window, simply click on it.
• When you exit the Main Window, the other windows go away.

Main Window ("command center") has the majority of settings and action buttons.

Map Settings Window customizes all map settings.

Other Settings Window:

• Click on "Other Settings" in upper right of Main Window.
• A separate "Other Settings Window" pops up.
• Casual users can mostly ignore the other options.
• Advanced users will appreciate the extra power. Help Window is what you are currently viewing.

Results Window displays any output maps or tables.

• Normally, each new result is appended to the Results Window.
• Review previous results by clicking on browser "Back" button. Chart Setting Windows modify bar, line, and pie chart settings.

Main Statistic

Table Axes (Rows and Columns)

Year	0-19	20-39	40-59	60+
1990	1,032	302	545	79
1991	1,134	317	555	88
1992	1,236	348	602	86

Example Table: Year Rows - Age Columns

• Rows - Horizontal lines of data, such as the row for 1991.
• Row Sort - Rows can be sorted, low to high, or high to low.
• Columns - Go up and down, such as the column for age 0-19.
• By Variable - Also called "Multi-Tables". Makes a series of tables.

Example Row Variable Selector:

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

Statistic / Axis Conflicts

If there is a conflict between statistic, rows, or columns:

• Vitalnet alerts you of the conflict (mismatch).
• Vitalnet does not allow a table until the conflict is corrected.

Examples of conflicting settings (mismatches) include:

• Race rows, race columns.
• Year rows, year columns.

To correct a conflict, select a different Main Statistic, Row Variable, or Column Variable.

Selecting Data Variables

Data variables include - age of mother, birth weight, race, county of residence of mother, delivery method, sex of baby, gestational age, prenatal care visits, year of birth.

Example selector for range variable, such as age or year:

Sample range variable selector

Range variable selector lets you easily:

• Shrink or extend ranges
• Delete highlighted ranges
• Split highlighted ranges
• Apply a standard grouping

Example selector for categorical variable, such as race or sex:

Sample range variable selector

Categorical variable selector lets you easily:

• Add a category as a set
• Merge sets into new set
• Split set into separate sets
• Delete a set

Statistic / Variable Conflicts

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 do not 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

Other Settings include the following options:

Statistic Modifiers:
• Early Care Cutoff - Early Prenatal Care % Month, such as 4
• Early Delivery Cutoff - Week for Early Delivery %, such as 37
• Reside / Occur - Residence or Occurrence Analysis

Secondary Statistics:
• Cell Confidence Level - Set Level, or Turn Off
• Cell Suppression - Hide Result if Low Count
• Table Percents - Row or Column Percents
• Trend Algorithm - Trend Analysis Method
• Trend Confidence - Set Level, or Turn Off

Miscellaneous Details:
• Decimal Digits - Example: Two in 5.78
• HTML Line Style - Line Style for Output HTML
• HTML Output Font - Text Font for Output HTML
• HTML Padding - Padding for Output HTML Table
• Spreadsheet Format - Spreadsheet Data Format
• Tabular Chart - Chart Width, or Omit Chart
• Unique ID - Put ID on Maps and Charts?

Bar Chart Coloring

• Background color behind the chart.
• Color palette to use for the bars.
• First color in palette to use for bars.

Below are shown the settings, with examples:

Background Color for Chart (20 options)

White

Grey 95

Lemon Chiffon

Light Cyan

Color Palette for Bars (4 options)

Bright Colors

Subdued Colors

Bright + Subdued

Black + White

First Color in Palette to Use (10 options)

A Forward

D Reverse

E Forward

J Reverse

Bar Chart Layout

Vertical or Horizontal Bars

Vertical Bars

Horizontal

Stacked Bars?

Stacked Bars

Not Stacked

Height of Each Bar (9 options)

2 cm High

4 cm High

Width of Each Bar (8 options)

0.2 cm Wide

0.6 cm Wide

Include Grid Lines?

Include Grid

Omit Grid

Font Size for Chart Text (8 options)

10 pt Font

14 pt Font

Line Chart Settings #1

Eight ways to customize Vitalnet line charts:

Background Color for Chart (20 options)

Alice Blue

Light Yellow

Include Data Point Symbols? (2 options)

Include Symbols

Omit Symbols

Radius for Chart Symbols (10 options)

1.0 mm Radius

1.4 mm Radius

Line Chart Height (9 options)

4.0 cm (Not Shown)

7.0 cm (Not Shown)

Line Chart Settings #2

Width of Lines (3 options)

Thin Lines

Thick Lines

Include Grid Lines? (2 options)

Include Grid

Omit Grid

Colored Lines, or Black + White (2 options)

Colored Lines

Black + White Lines

Font Size for Chart Text (8 options)

10 pt Font (Not Shown)

12 pt Font (Not Shown)

Pie Chart Coloring

Three settings for customizing pie chart coloring:

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

Background Color for Chart (20 options)

Cornsilk Background

Grey Background

Light Cyan

Color Palette for Pie Chart (3 options)

Bright Colors

Subdued Colors

Mixed Colors

Slice #1 Color to Use (10 options)

Color A for #1

I Forward

F Reverse

Pie Chart Layout

Four settings for customizing pie chart layout:

Slice #1 Clock Position (12 options)

Slice #1 at Noon

Slice #1 at 3:00

Slice #1 at 6:00

How to Label Pie Chart (9 options)

Line + Label

Label Only

Use Legend

How to Display Slice Percents (3 options)

Percent After Label

Under Label

Omit Percents

Pie Chart Radius (9 options)

3.0 cm (Not Shown)

4.0 cm (Not Shown)

5.0 cm (Not Shown)

Tabular Charts / Chart Links

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 (36 options)

Orange-Red

Grey

Red-Blue

Number of Colors (8 options)

3 Colors

5 Colors

7 Colors

How to Set Ranges (3 options)

Equal Ranges

Equal Counts

Natural Breaks

Map Layout

Boundaries to Display (2 options)

County Boundaries

HSR Boundaries

Border Counties

Cell Suppression (14 options)

Suppression Off

Suppress if < 10 Events

Suppress if < 30 Events

Map File Format (PNG, PDF, SVG, GIS)

PNG Map (Imports Best)

SVG Map (Prints Best)

GIS Map (Interesting)

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-Green	Y	Y
									Purple-Red	Y	Y
									Purple	Y	Y
									Red-Purple	Y	Y
									Red	Y	Y
									Yellow-Green	Y	Y
									Yellow-Blue	Y	Y
									Yellow-Brown	Y	Y
									Yellow-Red	Y	Y

All palettes are OK for color printing. BW - OK for black and white printing? CB - OK for red-green color blindness?

References for Vitalnet map color 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 showing color palettes.

Getting Results

To produce results:

1. Click on button - Click on "Make Map NOW" or "Make Table NOW". 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

To view results:

1. Scroll results - Use scroll bar, PgUp, PgDn, etc.
2. Print or Save results - Sends to printer or disk.
3. Click on footnote links - Access charts and data files.

If graphics do not display in output, refresh the browser.

Printing Results

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 link for desired format in output footnotes.
2. Download and import the data file:
• CSV / TSV / DIF for spreadsheets, 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

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 - Import into word processing software.
• CSV/TSV/DIF format - Import into spreadsheet software.
• dBASE III - For database, GIS, mapping, stats software.

To save a map as an image file, minus any surrounding text:

1. Position cursor over map, using your mouse.
2. Press right mouse button to bring up popup menu.
3. Select "Save" option from popup menu.
4. Specify directory (folder) to save 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 provided unique ID for data files, such as "112jdhkm.dbf".

When Charts and Maps are Made

Vitalnet is smart about making output. Whenever you make a table, Vitalnet usually makes one or more accompanying charts. But it only produces the charts that make sense. If a chart would look terrible, or not be epidemiologically valid, the software does not make it.

Vitalnet avoids making misleading or useless charts. To prevent misinterpretation and embarassing results, Vitalnet intelligently decides when it appropriate to make a chart, as explained below:

Bar charts are only made if the following conditions are met:

• 1 to 20 rows (groups of bars).
• 1 to 10 columns (bars per group).
• No suppressed results (for stacked bar chart).

Line charts are only made if the following conditions are met:

• Range rows (such as age or year).
• No breaks in ranges (not 2000, 2002).
• Rows not sorted. No suppressed results.
• No more than 10 lines (10 columns).

Pie charts are only made if the following conditions are met:

• Cumulative data (counts, some rates).
• One set of numbers (one row or column).
• 2 to 9 pie slices. No suppressed results.

Time trend maps (that cycle from map to map) are only produced when all selected year ranges are the same width. For example, 1995-1996, 1997-1998, 1999-2000 is OK. But 1995-1996, 1997-1998, 1999 is not OK. Also, at least two year ranges are required. So if you just have 1995-1996 (a single range) selected, Vitalnet does not make a series of time trend maps.

Time trend analysis, when making a table with year rows, is only carried out when: 1) at least three year ranges are selected, 2) there are no gaps in the ranges, 3) the ranges are the same width, and 4) the rows are not sorted. When these conditions are met, the time trend analysis is epidemiologically valid.

Glossary

Apgar score - A summary measure of the condition of the infant based on heart rate, respiratory effort, muscle tone, reflex irritability, and color. Each factor is given a score of 0, 1, or 2; the sum of these five values is the Apgar score, ranging from 0 to 10.

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.

Birth rate - Births per 1,000 female or total population.

Birth weight - The weight of an infant at delivery, expressed in grams.

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 events (such as 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 may be displayed.

Cesarean rate - Number of cesareans / number of births.

Cesarean rate - primary - FC / (FC + FV). Numerator is number of first-time cesarean deliveries (FC). Denominator is number of first-time cesarean deliveries (FC) plus number of first-time vaginal deliveries (FV).

Cesarean rate - repeat - RC / (RC + VA). Numerator is number of repeat cesarean deliveries (RC). Denominator is number of repeat cesarean deliveries (RC) plus number of vaginal deliveries after previous cesarean (VA).

CNM - Certified Nurse Midwife (birth attendant category)

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, so 23-24 is more reliable than 13-34. 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 warehouse - A software system, such as Vitalnet, making large complex databases readily available for querying and analysis. A related term is "data mining", finding unexpected relationships in a data set, for further study. Data mining is 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.

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.

DO - Doctor of Osteopathy (birth attendant category)

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 10-19 is a filter variable.

FIPS Code - FIPS = "Federal Information Processing Standards". A five-digit number which uniquely identifies counties, territories, and certain other areas in the United States. States have two-digit FIPS codes.

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.

General fertility rate - Total live births (to all women) per 1,000 women age 15-44 in a given year.

Gestational age - Number of completed weeks elapsed between: the first day of the last normal menstrual period, and the date of delivery. Gestational age is expressed in completed weeks.

General fertility rate - Live births per 1,000 women age 15-44 in a given year.

Header - First part of a Vitalnet table. Lists key analysis parameters, such as years analyzed.

High birth weight - A birth weight 4,000 grams or greater.

High birth weight percent - Percent of births with birth weight 4,000 grams or greater.

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.

Infant - An individual less than one year of age.

Infant death - Death of a liveborn infant from the moment of birth to the end of the first year of life.

Intrauterine growth retardation - Birth weight in the lowest decile of birth weight for gestational age. An alternative definition is birth weight less than 2,500 grams (low birth weight) in a full-term infant (born at or after 37 weeks gestation).

Kessner adequate percent - Numerator is number of births with adequate Kessner index. Denominator is number of births with known Kessner index (unknown Kessner scores are not included in denominator). This is a measure of the adequacy of prenatal care. A higher Kessner adequate percent for a population indicates better prenatal care.

Kessner index - Method of categorizing adequacy of prenatal care, based on month of pregnancy care started, number of visits, and length of gestation. This takes both amount and start of prenatal care into account, and adjusts for the fact that women with short gestations have less time in which to make prenatal care visits.

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.

Live birth order - Live birth order is the number of children born alive to a mother, including the current baby. If the mother has three previous live births, the live birth order for the next birth is four. Another example: If the mother has one previous live birth, and has twins this time, the live birth order for the first twin is two, and is three for the second twin.

Low birth weight - A birth weight less than 2,500 grams (5 pounds, 9 ounces).

Low birth weight percent - Percent of births with birth weight less than 2,500 grams (5 pounds, 9 ounces).

MD - Doctor of Medicine (Physician) (birth attendant category)

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.

Neonatal death - Death of a liveborn infant within the first 27 days, 23 hours, and 59 minutes of life.

Neonatal death rate - Numerator = neonatal deaths x 1000. Denominator = number of liveborn infants.

Neonatal period - Period from birth through the first 27 days, 23 hours, and 59 minutes of life.

Neonate - A newborn infant during the first 27 days, 23 hours, and 59 minutes of life.

Perinatal period - Period from the 20th completed week of gestation (140 days) through the first 27 days, 23 hours, and 59 minutes of life.

Place of occurrence - The geographic location where a birth occurred.

Place of occurrence birth data - Data compiled by the location where the birth occurred, without regard to the place of residence of the mother.

Place of residence - The geographic location where a birth occurred.

Plurality - Number in a birth, such as twins or triplets.

Population - The number of people living in an area.

Postneonatal - Period between 28 days and one year of age.

Post term birth - Birth after the 41st week of gestation. Birth during or after the 42nd week of gestation.

Preterm birth - Birth occurring before the 38th week of gestation. Birth occurring during or before the 37th week of gestation.

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.

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 - basic analysis settings
2. Data section - numerical results
3. Bar graphs - horizontal charts
4. Footer - 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.

Term birth - Birth during the four week period after the 37th week of gestation and before the 42nd week of gestation. Birth during the 38th through 41st week of gestation.

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.

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.

Very low birth weight - A birth weight less than 1,500 grams (3 pounds, 5 ounces).

Very low birth weight percent - Percent of births with birth weight less than 1,500 grams (3 pounds, 5 ounces).

Vitalnet / VitalPro / VitalWeb - Vitalnet is data warehouse / data analysis software for analyzing health data sets. VitalPro is a Vitalnet system that runs directly on a PC, for example VitalPro for Win32. VitalWeb is a Vitalnet system that runs over the internet, for example VitalWeb Ajax.

Windows - Microsoft PC operating systems. VitalPro 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.

Race Categories

California Race Groupings Used
1999 and earlier	2000 and later
Five Groupings: - American Indian - Black - Hispanic - White - Asian / Pacific Islander	Seven Groupings: - American Indian - Black - Hispanic - White - Asian - Pacific Islander - Two or More Races

County Groupings

Health Service Area 1: Butte, Colusa, Del Norte, Glenn, Humboldt, Lake, Lassen, Mendocino, Modoc, Plumas, Shasta, Siskiyou, Tehama, Trinity

Health Service Area 2: El Dorado, Nevada, Placer, Sacramento, Sierra, Sutter, Yolo, Yuba

Health Service Area 3: Napa, Solano, Sonoma

Health Service Area 4: Marin, San Francisco, San Mateo

Health Service Area 5: Alameda, Contra Costa

Health Service Area 6: Alpine, Amador, Calaveras, Merced, San Joaquin, Stanislaus, Tuolumne

Health Service Area 7: Santa Clara

Health Service Area 8: Monterey, San Benito, San Luis Obispo, Santa Cruz

Health Service Area 9: Fresno, Kern, Kings, Madera, Mariposa, Tulare

Health Service Area 10: Santa Barbara, Ventura

Health Service Area 11: Los Angeles

Health Service Area 12: Inyo, Mono, Riverside, San Bernardino

Health Service Area 13: Orange

Health Service Area 14: Imperial, San Diego

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.

Births - The number of live births.

Birth Weight Percent - Percent of births that are either:

- Low birth weight = Under 2500 grams
- Very low birth weight = Under 1500 grams
- High birth weight = 4000 grams or over

Cesarean (CS) Rate - One of the three following rates:

- Total = Total cesareans / Total live births
- Primary = First CS / (First CS + First-time vaginal)
- Repeat = Repeat CS / (Repeat CS + Vaginal after CS)

Note: Births with unknown delivery method are excluded from calculation of cesarean rates.

Early Prenatal Care Percent - The percent of births where the mother received care by or before a certain month, such as the third month of pregnancy.

Adequate Prenatal Care Percent - The percent of births with "adequate prenatal care" Kessner index.

Birth Rate per 1,000 Total - Births per 1,000 total population. Also known as "crude birth rate" or "live birth rate".

Birth Rate per 1,000 Women - Births per 1,000 female population.

General Fertility Rate - Total number of births to women of any age, multiplied by 1,000, divided by the number of women age 15-44.

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 do not 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

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 Ajax uses data from authoritative sources.

Birth data - All California birth data were provided by the Department of Health Services / Office of Health Information and Research.

Population data - All California population data were provided by the Department of Finance.

Links to Related Resources

Internet resources related to Birth Data:

• Center for Health Statistics - California Department of Health Services

Whom to Contact

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

• Center for Health Statistics - 916-552-8096

Legal Information

Data Awarehouse, "Discover the future of health data", "We care about your health data", Birtha, Epidemic, Epigram, Medtrend, Multicod, Oncogram, Poptrend, Pregdata, STD Wizard, Vitalnet, VitalWeb, VitalPro, VitalPro for Win32, VitalPro for Unix, VitalPro for Windows, VitalWeb Ajax, VitalWeb Standard, and VitalWeb Wizard are trademarks of Daniel Goldman. VITALNET and VITALWEB are registered trademarks. More information

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California Birth Data VitalWeb Ajax Online Help

Table of Contents

Quick Guide to Using VitalWeb Ajax

Multiple Windows

Main Statistic

Table Axes (Rows and Columns)

Statistic / Axis Conflicts

Selecting Data Variables

Statistic / Variable Conflicts

Other Settings

Bar Chart Coloring

Bar Chart Layout

Line Chart Settings #1

Line Chart Settings #2

Pie Chart Coloring

Pie Chart Layout

Tabular Charts / Chart Links

Map Coloring

Map Layout

Map Color Palettes

Getting Results

Viewing Results

Printing Results

Saving Results

When Charts and Maps are Made

Glossary

Race Categories

County Groupings

Statistical Methods

Confidence Intervals

95% Poisson Confidence Limits

Data Sources and Limitations

Links to Related Resources

Whom to Contact

Legal Information

California Birth Data
VitalWeb Ajax
Online Help