Friday, November 20, 2009

Biometric and Other Identification Technologies

In my November 17 post, I began a discussion of the [proposed] unique patient identification numbers by looking at a de facto proxy, the Social Security number (SSN). In the present post, I will continue with a look at a few of the technologies available for getting information such as someone's identification into or out of a computerized system such as, but not limited to, those used to implement electronic health records (EHR).

Biometric Applications

Biometric verification is a technology which uses unique characteristic features of an individual to automatically identify a person. There are several biometric technologies including fingerprint, hand geometry, and retinal scan. Each of these verification techniques claims to provide positive identification of individuals. What's more, these forms of ID cannot be transferred, forgotten or lost. Anywhere personal identification is required (such as PIN numbers at financial institutions), biometric verification can be used.

The hardware needed for biometric verification is frequently installed at the entrance of a building or secured area and are the "keys" for entry. Fingerprint verifiers, for example, generally allow any finger on either hand to be used for positive identification. Usually an alternate finger is also chosen as a backup in case of injury (cut, scrape, etc.) to the first. Multiple fingerprint templates can be stored locally inside the fingerprint terminal or through a network on a host computer (e.g., in a database). Most vendors also include software that supports common security access features such as unauthorized overtime or early clocking in. In addition, many of these systems can be integrated with existing software packages. Therefore, usually, separate systems do not have to be maintained in order to record and restrict access.

Biometric applications are highly specialized and costly to install when compared to card recognition and other access systems. In addition, if a biometric unit such as a terminal goes down, the manufacturer is often the only source for replacement or repair. With other technologies, such as magnetic stripe, input devices are readily available and can be purchased from a variety of vendors. Biometric Identification, however, does have its benefit. When ultimate security is vital, biometric identification is sometimes proven to be the best solution. But, caveat emptor: as shown later in this post, errors do occur.

Voice Recognition

Although technically, voice recognition is part of biometric verification, its widest application is to convert speech into text and not principally for security or access control. Voice recognition has many advantages, most notably allowing people to keep their eyes and hands free while "voicing instructions" to the computer. Voice recognition is used in many professional fields including healthcare.

For a discussion of using the human voice for verification, see my article "Speech Authentication Strategies, Risk Mitigation, and Business Metrics" in the bibliography at the bottom of this blog.

For readers with a background in mathematics and statistics, see the papers

"Comparing Human and Automatic Face Recognition Performance" at


"Statistical Evaluation and Estimation of Biometric-based Classification" at

Among the topics discussed here are

(1) false accept rate
(2) false reject rate
(3) false match rate
(4) false non-match rate
(5) biometric authentication,
(6) effective sample size
(7) confidence intervals

Note 1: A video in the right-hand column of this blog presents a brief introduction to confidence intervals.

Note 2: If 99.9% were good enough

• There would be a major plane crash every 3 days
• 12 babies would be given to the wrong parents each day
• There would be 37,000 ATM errors every hour

Nonetheless, technology-based systems in use today do yield the expected outcome less than 100% of the time.

So, it's important that you understand that, like their human counterparts, technologically-based methods are error prone. At the same time, it's also important that you know the cost of these errors to you (and those you serve) in the methodology you choose to use.

Optical laser Cards

These cutting-edge cards transform CD-ROM technology into a credit card form, capable of securely storing megabytes of personal information. For example, a patient ID card could hold an image, health care history, vaccination record, X-rays and more.

Card Based Access System

Controlling entry security to your facility (or computer system) is of vital importance, whether your facility is a high security area such as a hospital, airport, or bank, or even if it is an everyday situation such as an insurance office, school, or department store.

Visual Identification

The simplest access control systems use portrait ID or membership cards, which rely on a receptionist or colleagues at work to recognize interlopers by the absence of a valid, matching portrait card. Such systems require the printing of clear, easily visible, portrait cards. Unfortunately however, that alone is not enough, because with current PC and scanner technology, creating fake or counterfeit cards is all too easy.

Even simple door entry control systems need to use an anti-counterfeiting system which provides an overall security "watermark" feature which is proof against all attempts to copy it.
This type of access control is extremely cost-effective, and it may be all that many facilities need to achieve the security level they require.

Swipe Card Door Access Control Systems

If you need controlled access without relying on the presence of guards or reception staff, you may need to add swipe card readers and electronic locks to your controlled entrances. A higher level of security can be achieved by using mag-stripe readers.

Proximity Cards / Prox Card Access Control Systems

Proximity Cards, or "Prox" as they are often called, are standard size plastic ID cards which contain a coil antenna and a pre-programmed micro chip containing a unique code. When the prox card is within a foot or so of the Prox reader, the radio signal from the reader is picked up by the card antenna and used to power-up the micro chip which then replies with its own unique code.

The reader and its associated processor compare the code with a list of authorized entrants, and if it's OK, the door is opened and a record of entry is logged.

Prox cards must always be "personalized" with a portrait ID to eliminate the misuse of "loaned" or stolen cards.

Reference Books

For a good summary of the sources of problems (errors) and biometric performance, see

This book includes very readable material on

(1) Legal aspects of biometric technologies
(2) Selected technology error rates
(3) Resistance of the system to forgeries
(4) RFID applications
(5) Economics

and much else.

For a comprehensive introduction to RFID, see

Click here
for a preview look at this book.

RFID and Bar Codes

For a discussion of the pros and cons of using RFID and bar codes for the identification of patients, staff and medications, in different use cases, see

You will find there a summary of early work at Beth Israel Deaconess Medical Center in Boston to establish positive patient identification:

"For identification of most patients, we believe linear and two dimensional bar codes on wrist bands is robust, cost effective and standardized. For staff badges, linear bar codes work well. For NICU babies passive RFID enables scanning of swaddled infants without disturbing them.

For identification of medications, we believe linear bar codes of NDC numbers on heat sealable plastic bags provides a practical means to positively identification medications.

For identification of equipment, specifically for tracking location in real time, active RFID works well. Because of the size and expense of tags, we do not believe active RFID should be used for patient identification at this time.

Thus, a combination of bar codes, passive RFID and active RFID is working well in our various pilots. No one technology meets the needs of all use cases. Although we favor bar codes over passive RFID in the short term, we do expect to eventually replace bar codes with RFID once the technology is more robust, standardized and cost effective."