Vital Signs

Out-of-pocket costs are expenses for medical care that insurance does not reimburse, including deductibles, coinsurance, copayments, and the full cost of services that are not covered. This post explains the term and reviews six studies: a 2026 claims analysis of 539,590 adults with diabetes or hypertension in high-deductible plans, a survey study of 147,254 adults linking high-deductible plans to survival among cancer survivors, 11 years of hospital cost sharing trends, and three studies of real-time benefit tools that show prescription costs in the EHR.

In the HIMSS Dictionary, LAN has more than one meaning; this post covers the Health Care Payment Learning and Action Network, launched in March 2015 through CMS to move health care away from volume-based fee-for-service payment. It explains how the network’s framework of alternative payment models is used and reviews five sources: a 2026 proposal that applies the framework to collaborative behavioral health care, an oral health payment framework with 4 categories and 9 mechanisms, a commentary on Medicare advanced APMs, a review of APMs and diabetes outcomes, and a five-level value-based payment maturity model.

The Health Alert Network, or HAN, is a public health capability intended to give each community rapid and timely access to emergent health information, trained personnel, and evidence-based practices for preparedness and response around the clock. This post explains the HIMSS Dictionary description and reviews five sources: a New York City project that turned HAN messages into EHR alerts with order sets, a review of public health alerts for EHR suitability, a 2022 monkeypox response that included a HAN Health Advisory, a 2024 dengue advisory, and a Spanish study of 242 Ebola inquiries.

Data linkage is the merging of information from two or more sources to consolidate facts, and also the technique of connecting records within and between data sets using demographic data such as name, date of birth, address, sex, and medical record number. This post explains the term and reviews five studies: a systematic review of privacy-preserving linkage in US real-world data, a bias framework built on a cohort of more than 131 million people, a Korean claims linkage quality study, a comparison of three methods on 2,247 patients with multiple sclerosis, and a Bayesian de-identified matching method.

Cognitive computing is a type of computing aimed at complex, ambiguous, and uncertain problems, where data are dynamic and may conflict, and where the goal is a decision that is best for the situation rather than a single right answer. This post explains the HIMSS Dictionary description and reviews six sources: two systematic reviews, a colon cancer study of 656 patients with 48.9 percent absolute concordance, a meta-analysis of 9 studies and 2,463 patients, a urologic oncology study with 92.7 percent concordance, and a pilot of an automated problem list.

An ACG, in the HIMSS Dictionary an Ambulatory Care Group and also known as an Adjusted Clinical Group, is a method of grouping outpatient episodes by expected use of resources, modified by principal diagnosis, age, and sex. This post explains the term and reviews six studies: an Ontario analysis of 11.4 million adults in 60 ACG levels, a comparison of comorbidity scales in 3,496 older adults, a Veneto region cost model, a hospital-only application in Singapore, a Norwegian validity study of 168,285 adults, and a 2026 test of machine learning on ACG features.

WEP, or Wired Equivalent Privacy, was the first security protocol for Wi-Fi networks, designed to give wireless links about the same privacy as a wired local network. This post explains the term as the HIMSS Dictionary describes it, why NIST guidance calls it inherently flawed, what replaced it, how the HIPAA Security Rule treats transmission over networks, and what two hospital wireless studies reported when WEP was still in use, in a prehospital network and a radiation oncology department.

A severity system estimates how likely a disease is to progress regardless of treatment, using diagnosis codes such as ICD codes, additional clinical information, or both. This post explains the idea and reviews five studies: APR-DRG severity subclasses that outperformed the Charlson index in 63,681 surgical visits, hourly ICU scores across 561,478 adult ICU patients, an automated VA ICU model built from routine data, sepsis risk adjustment with EHR data, and a study of how many diagnoses are present on admission.

A patient administration system, or PAS, is the hospital system that captures and stores patient identifying details and a record of each patient’s contacts with the hospital, and that supports admissions, transfers, discharges, and appointments. This post explains the term and reviews five studies: an ethnographic study of a rural PAS rollout across 10 agencies, a validation of 140 PAS outpatient records, a comparison of PAS and clinician-collected data, a child welfare data match of 1,683 children, and a review of keeping a national PAS sustainable.

The Clinical Decision Support Knowledge Artifact Specification, or KAS, is an HL7 standard that gives guidance on writing shareable decision support content in XML, including event-condition-action rules, order sets, and documentation templates. This post explains what a knowledge artifact is, how the HL7 specification evolved to use the Clinical Quality Language, and what five studies found on sharing CDS: a RAND prototype that built 22 artifacts, a national CDS Connect evaluation, a survey of 13 knowledge repositories, and two standards-based CDS projects.

An integrated delivery network, or IDN, is a formal system of providers and sites of care that delivers health care services and also offers a health insurance plan to patients in a geographic area. This post explains the structure and why it matters for health IT, then reviews four studies: how centralized IT governance related to technology adoption across 485 systems, the total cost of robotic surgery across 14,315 procedures, lung cancer screening completion across 51 primary care clinics, and a pharmacy workflow system rolled out in three hospitals.

An electronic audit trail is the record that an electronic medical record system keeps of who logged in, accessed, or changed patient information, and when. This post explains what the HIMSS Dictionary says about its uses, what the HIPAA Security Rule requires for audit controls and regular activity review, and what four recent studies learned by analyzing EHR audit logs: modeling 295 million actions with a language model, identifying ICU care teams, finding the daily frontline clinician, and measuring the real documentation-time effect of AI scribes.

A clinical informaticist is a clinician who uses knowledge of patient care together with informatics methods and tools to analyze, design, implement, and evaluate information and communication systems that improve health outcomes and care. This post explains the role as the HIMSS Dictionary describes it and reviews four studies: the workforce of 2,018 certified clinical informatics physicians, a practice analysis with 5 domains and 42 tasks, a UK competency framework with 111 competency statements, and a 2026 effort to refine the definition.

An ATCB, or Authorized Testing and Certification Body, is an entity that tests and certifies EHR technology against the standards, implementation specifications, and certification criteria adopted by the Secretary of Health and Human Services. This post explains the term, how the current ONC Health IT Certification Program in 45 CFR Part 170 separates certification bodies (ONC-ACBs) from testing laboratories (ONC-ATLs), and what recent studies found about real world testing results and safety-critical certification criteria.

VoIP, or Voice over Internet Protocol, carries voice conversations over an internet connection instead of a traditional analog phone line by digitizing speech into packets and reassembling it in real time. This post explains how it works, what NIST says about its security challenges, and what three studies found: a pilot trial of therapy delivered by VoIP for youth with chronic tic disorders, a cochlear implant study of Skype versus conventional telephony, and a study of mobile VoIP versus standard mobile calls.

System testing is the phase of software testing in which a complete, integrated system is tested against its specified requirements as a black box. This post explains how it differs from unit, integration, and acceptance testing, and reviews three kinds of evidence on testing EHR safety: the SAFER Guides and the finding that eight organizations fully implemented only 18 percent of 140 recommendations, the 2025 revision of the Guides, and a study of 1,183 hospitals tested with simulated orders and patients.

Under HIPAA, psychotherapy notes are notes recorded by a mental health professional that document or analyze the contents of a counseling session and are kept separate from the rest of the patient’s record. This post explains what the definition includes and excludes, why an authorization is generally required to use or disclose them, why they fall outside the right of access, and what studies found about open notes in mental health care.

Normalization has two meanings in health IT: creating a uniform, agreed set of standards, policies, definitions, and technical procedures so systems can interoperate, and organizing the fields and tables of a relational database to reduce redundancy. This post explains both and reviews three studies: a survey in which 19.6 percent of reported LOINC codes were incorrect, a 32-author consortium that normalized structured and unstructured EHR data for quality measures, and an FHIR-based pipeline with 62 normalization rules.

The Health Quality Measure Format, or HQMF, is an HL7 standard that represents a quality measure as an electronic document containing the information needed to compute the measure and its result. This post explains how HQMF works and how it relates to eCQMs and Clinical Quality Language, and reviews studies that translated HQMF queries into i2b2, executed measures at scale with MapReduce, and implemented 39 national quality indicators in CQL on FHIR.

Electronic clinical quality improvement, or eCQI, is the use of common standards and shared technologies to monitor and analyze the quality of health care and patient outcomes. This post explains how eCQMs fit within eCQI and reviews three recent development and testing studies: three neurocritical care measures tested at three sites, a pulmonary embolism measure whose accuracy depended on standardized coding across 38 emergency departments, and two pneumonia antibiotic measures tested in 109 VA systems and two academic centers.