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Vitalnet BRFSS Module |
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A. Introduction
The BRFSS is a rich source of public health data. However, BRFSS data are quite complex to analyze. Sources of the complexity include:
Vitalnet will make it much easier for data analysts, researchers, health agencies and public users to analyze BRFSS data. The result will be better use of BRFSS data for improving US public health. 
B. Brief Description of BRFSS From the CDC BRFSS web site: The Behavioral Risk Factor Surveillance System (BRFSS) is the world's largest, on-going telephone health survey system, tracking health conditions and risk behaviors in the United States yearly since 1984. Currently, data are collected monthly in all 50 states, the District of Columbia, Puerto Rico, the U.S. Virgin Islands, and Guam. BRFSS data have historically been analyzed two ways: 1) Certain commercial generic stat packages (GSP). 2) Web-based home-grown software (HGS), developed by the CDC and some States. C. Vitalnet Compared with Generic Stat Packages (GSP) How useful is a GSP for analyzing BRFSS data? - "Generic stat packages" include SAS, SPSS, SUDAAN, and Stata. They are powerful, general purpose, and flexible. 
In the hands of a trained expert, some GSPs can correctly analyze complex survey data such as BRFSS data.
SUDAAN is specialized for complex survey data.
Others have specialized modules for complex survey data.
However, using a GSP is far beyond the capability of the great majority of users. Even in expert hands, using a GSP is quite complex, error-prone, awkward, and time-consuming. The user needs to understand many details about BRFSS file layouts, BRFSS variables, and how to use the complex software. Also, a GSP is typically not cheap. There are licensing costs and expensive, time-consuming training. How does Vitalnet provide much better usability? - Vitalnet is a new and fundamentally different kind of stats package. We've taken a new approach to greatly simplify data analysis. Vitalnet is definitely not "generic". Vitalnet is specifically and totally customized for analyzing BRFSS data (or other data set), for a particular jurisdiction. Vitalnet "knows" all about the data set. Instead of the confusing array of statistical tests offered by a GSP, Vitalnet offers exactly the options the user might need, in a fully menu-driven format. Instead of the arduous, error-prone task of setting up a GSP analysis, the user merely has to choose options from self-explanatory Vitalnet menus and press "Go". Training needs are minimal. For both occasional and expert users, Vitalnet is much easier, more reliable, and more useful. Here are a few ways Vitalnet BRFSS is better than a GSP for analyzing BRFSS data:
D. Vitalnet Compared with Home-Grown Systems (HGS) How useful are CDC and State home-grown systems? - Everyone realizes that using a GSP is impractical for the great majority of users to analyze BRFSS and other public health data. Web-based home-grown systems (HGS), as developed by the CDC and some States, 
are a step in the right direction, to make BRFSS and other data easier
to access and analyze. But in practice the HGS have failed to meet the need.
They lack too many needed capabilities, and cost too much to develop and maintain.
Developing and maintaining data warehouse software is very complex. With Vitalnet software, government agencies can get out of trying to be in the software development business, and get back to their public health mission. With Vitalnet software, government health agencies can smoothly and efficiently make best use of their data, at much lower cost, to improve public health. How does Vitalnet provide much better usability? - Vitalnet BRFSS provides the needed combination of analytical flexibility, ease-of-use, and output capabilities, in a professional software system. Vitalnet empowers any user to quickly make the needed table or other output. Each HGS is somewhat different, with it's own strengths, weaknesses, and quirks. Based on direct usage, here are some ways Vitalnet BRFSS is better than home-grown BRFSS systems:
E. BRFSS Vitalnet Development and Current Status Background research - We have appreciated the usefulness of BRFSS data for many years. To refresh our understanding, we reviewed CDC and State BRFSS reports, and the extensive technical documentation on the BRFSS web site. 
We also looked at existing home-grown web-based systems.
Our reviews helped us better understand the nature of BRFSS data,
and how the data are currently used.
Database design - Next, we designed a novel record-level database architecture specially optimized for BRFSS data. This was a key step. The special database design results in low disk space requirements, rapid analyses, and retention of record-level detail. The special design outperforms generic database designs used by alternative solutions. Vitalnet data importing routines were modified, to rapidly and reliably import BRFSS data into Vitalnet. Database engine - The Vitalnet database engine (the functions that read the database and produce the needed results) was modified to read the new database architecture. New C functions were written to take into account BRFSS weighting and produce the "primary statistics" needed for BRFSS data, such as "weighted %yes". Interface / outputs - 
Next, we modified the existing
VitalPro for Unix,
VitalPro for DOS,
VitalWeb Standard and
VitalWeb Wizard
interfaces to provide additional BRFSS-specific menu options.
The BRFSS interface uses the same "look and feel" as other Vitalnet modules,
making it easy for users to switch between data sets.
Finally, Vitalnet output formats were modified to handle the
BRFSS numerical results, and to include the BRFSS-specific
documentation needed to prevent misinterpretation of results.
Confidence intervals - Calculating confidence intervals (CI) for BRFSS data is complex. Several CI methods are available for for BRFSS data. We chose "Jackknife Replication" (JR) mainly because 1) It can calculate confidence intervals for any outcome, including medians, and 2) JR seemed easier to understand and explain. JR recalculates the outcome, such as "% Yes", many times, each time leaving out one or a few observations, and re-weighting the remaining observations. Each recalculation is called a "replicate". Then, it calculates the confidence interval based on the distribution of the replicate outcomes. The method is called "jackknife" because it is so generally useful, like a jackknife. "Taylor series linearization" (TS) converts each observation to a "linearized variable". Then, it calculates the confidence interval based on the distribution of the linearized variables. Based on comparisons we have done, TS and JR produce essentially the same results. TS cannot calculate confidence intervals for medians. There is no way around this disadvantage. JR is computation-intensive and can be slow. However, we have optimized JR to make it much faster (typically a few seconds). Also, we have determined that a JR CI with smaller numbers of replicates is essentially the same as one with an unlimited number of replicates. For exploratory data analysis, the user can use a smaller number of replicates. For published results, "unlimited replicates" is recommended. We may add TS as an option in the future, to speed up CI analyses in some cases. Validation of Vitalnet JR confidence intervals. Verification that low # of JR replicates is similar. Current status - Currently, over 70 BRFSS variables are incorporated into the Vitalnet module. More variables can be added, as needed or requested. More years of data will be added in the future. At that point, mechanisms will be added to take into account changes in questions asked over the years. We plan to add age-adjusted outcome measures. Also, maps will be added, similar to the mapping in other Vitalnet modules. The program has been extensively tested, both for internal consistency and in comparison with printed reports from the BRFSS web site and results from CDC WEAT. No data errors have been detected. F. Examples of BRFSS module output Below are links to some simple examples of output produced by the new BRFSS module. Each example took less than a minute to design and produce. The examples illustrate output capabilities not available with GSP and HGS tools.
G. Additional Information How can we help you? - If you would like more information about Vitalnet BRFSS module, please fill out feedback form. Or call us at 888-709-5319 (PST). 
If you would like to license Vitalnet BRFSS, we would be happy to
discuss your requirements for a fully working version for your agency or State,
along with birth, death, and other modules of your choosing.
Vitalnet can be rapidly and reliably customized for use by your State.
You will get best performance and usability, at the lowest cost.
Your State-specific BRFSS questions will be included as you specify.
How can you help us? - If you have any suggestions for additional ways of analyzing BRFSS data, we are interested to hear. 
We have a unique combination of public health and software expertise
that allows us to create incredibly useful health data analysis software.
We are always learning and readily admit we don't know everything.
You may have different ways of analyzing and displaying BRFSS data we have not anticipated.
We welcome your requests, ideas, suggestions and error reports. We will customize your Vitalnet software as required to make better use of the data. We want to help you accomplish your goals, succeed, and enjoy your work. We are confident BRFSS data will be even more useful for you and your users in the future, as Vitalnet BRFSS module is improved and used. General information on Vitalnet - Vitalnet is a professional data warehouse solution, the product of over 10 years of development. It analyzes health data or any record-level data, including birth, death, pregnancy, hospital discharge, and many more. Vitalnet runs on a PC desktop and via internet in a web browser. For an affordable annual fee, you get better usability than any other commercial or home-grown data warehouse system. Only Vitalnet provides the needed combination of ease-of-use, speed, analytical flexibility, data visualization, scalability, and reliability to meet your requirements and satisfy your users. You retain full control over all data policy and customization issues. Full support is provided, including data importing. Try out VitalWeb (Vitalnet browser platform) for free. Fill out contact form (or call 888-709-5319). | |||||||||||||||||||||||||||||||||||
