Information system development life cycle models Essay
Information system development life cycle models
Health information managers must understand the components of information systems and how information systems affect the organization, individuals within the organization, and interested publics outside the organization. Information systems provide opportunities to improve internal operations, create competitive advantage in the marketplace, improve patient-care delivery, enhance research, and provide better service.
Information system risk occurs when the systems are not well integrated, are poorly managed, or do not support the goals of the organization. In order to exploit information system opportunities and minimize threats and risks, a thorough understanding of information system components and how these relate to the organization is necessary.
An information system is composed of a group of components (people, work processes, data, and information technologies) that interact through defined relationships to accomplish a goal. Information systems must be able to adapt to environmental change. A good example of a health-related information system is an order entry system. The goal of the system is to process physician orders.
The system is composed of a group of components including people (nurses, physicians, unit secretaries, laboratory personnel), data, work processes, and information technologies. Each of these components interacts through defined relationships. fails to accommodate the environment or if the interactions among its component parts fail, the system becomes nonfunctional and disintegrates. Thus, a system must be composed of a group of components that: Interact through defined relationships
Work toward accomplishing a goal
Self-adapt and respond to environmental changes
Figure 2-1 provides an example of the relationship of these characteristics. An information system is composed of a group of components (people, work processes, data, and information technologies) that interact through defined relationships to accomplish a goal. Information systems must be able to adapt to environmental change. A good example of a health-related information system is an order entry system.
The goal of the system is to process physician orders. The system is composed of a group of components including people (nurses, physicians, unit secretaries, laboratory personnel), data, work processes, and information technologies. Each of these components interacts through defined relationships
The peoples enter orders in a predefined way through a data entry terminal (hardware) and through interaction with software. Through the predefined interactions between the hardware and software, the order is processed.
The order entry system is self-adapting and able to accommodate environmental changes such as order volume. The example depicted in Figure 2-2 demonstrates the characteristics of a system as applied to an information system: component parts working in predefined relationships that can self-adapt to environmental changes to accomplish a common goal. As the bidirectional arrows depict in Figure 2-2, at any given time there is a potential three-way interaction between all system components. People interact or are affected by work practices, data, and information technologies.
Work practices affect people and may be impacted by data availability and information technologies. Information technologies may affect work practices, people, and the input, processing, or dissemination of data.
Thus, we see that information components are highly interrelated. Recognizing these interrelationships is very important, since a problem with one component will likely adversely impact all other components within an information system. When information system problems arise, it is crucial that all information system components and their relationships be examined
Systems have three principal elements: inputs, processing mechanisms, and outputs. Figure 2-3 depicts their simple relationship. In the order entry example given previously, inputs include physician orders such as laboratory, radiology, or pharmacy orders that are entered in a computer terminal on the patient-care unit. The orders are subjected to several processing mechanisms that check their consistency and completeness before they are routed to the appropriate department. The output of the system is a requisition for a specific type of test, procedure, or pharmaceutical.
In addition to inputs, processes, and outputs, most systems also have a feedback loop. Feedback provided by the system influences future inputs. In the order entry example, feedback regarding nonavailability of an ordered drug in the pharmacy department inventory might be provided to the physician. In this case, the system might suggest what alternatives or substitutes are available
Information System Components
All definitions of an information system must embody the essence of the four system characteristics that were previously presented. Thus, an information system is a group of interrelated and self-adapting components working through defined relationships to collect, process, and disseminate data and information for accomplishment of specific organizational goals.
The components of an information system should be broadly interpreted. For example, information system components should be viewed to include people, work procedures, data, and information technologies (Alter, 1992). Although organizational goals may not be specifically included in the components of an information system, they must be viewed as the driving force for the development, design, implementation, and evaluation of information systems. Each information system must be evaluated in terms of its contribution to meeting the goals of the organization Information System Types
In Chapter 2, six types of information systems are discussed: transaction processing systems (TPS), management information systems (MIS), decision support systems (DSS), executive information systems (EIS), expert systems (ES), and office automation systems (OAS). Early systems in health care were principally transaction processing systems. These systems automated operational functions such as accounting, payroll, inventory, and admission/discharge systems. Later, other transaction systems, such as order entry, were added to the capabilities.
Management information systems emerged in the late 1970s and gradually became more sophisticated during the 1980s. One factor influencing the growth of MIS during this period was the introduction of the national prospective payment (diagnostic-related groups or DRGs) system for Medicare patients. Because of DRG implementation, hospitals needed information systems that provided better filtered and formatted data for making managerial and strategic decisions.
The implementation of DRGs also revealed the weaknesses of current information systems in linking and integrating data. Weaknesses associated with the proliferation of stand-alone systems and the historical emphasis on financial systems became magnified during the 1980s coiera
When the same kind of decision is made on a regular basis, it will require access to the same kind of data and may use the same knowledge. In these circumstances, one can develop a regular process or information system to accomplish the task. An information system could thus be anything from the routine way in which a clinician records patient details in a pocket notebook, the way a triage nurse assesses patients on arrival in an emergency department, through to a complex computer-based system that regulates payments for healthcare services. An information system is distinguished from other systems by its components, which include data and models. Recall from the last chapter that there are several different kinds of information model, including databases and knowledge bases.
These different information components can be put together to create an information system. For example, consider a calculator that can store data and equations in its memory. The data store is the calculator’s database, and the equation store is its knowledge base. The input to the calculator becomes the equation to be solved, as well as the values of data to plug into the equation. The database communicates with the knowledge base using a simple communication channel within the device, and the output of the system is the value for the solved equation (Figure 3.6).
There are many potential internal components that could be included within an information system, including a database, a knowledge base, an ontology, and decision procedures or rules of inference. The different components of an information system are connected together with input/output channels, which allow data to be shifted between the components as needed.
A patient record system is a more complex example of an information system. Its purpose is to record data about particular patients in some formalized fashion to assist in the control Wager2009 An information system (IS) is an arrangement of information (data), processes, people, and information technology that interact to collect,
process, store, and provide as output the information needed to support the organization (Whitten & Bentley, 2005). Note that information technology is a component of every information system.
Information technology is a contemporary term that describes the combination of computer technology (hardware and software) with data and telecommunications technology (data, image, and voice networks). Often in current management literature the terms information system and information technology are used interchangeably.
6.1.1 What Is a System?shortliffe
Until now, we have referred informally to health information systems and computer systems. What do we mean when we refer to a system? In the most general sense, a system is an organized set of procedures for accomplishing a task. It is described in terms of (1) the problem to be solved; (2) the data and knowledge required to address the problem; and (3) the internal process for transforming the available input into the desired output (Figure 6.1). When we talk about systems in this book, we usually mean computer-based (or just computer) systems. A computer system combines both manual and automated processes; people and machines work in concert to manage and use information. A computer system has these components:
● Hardware: The physical equipment, including processing units (e.g., the central processing unit (CPU)), data-storage devices, comunication equipment, terminals, and printers ● Software: The computer programs that direct the hardware to carry out the automated processes—i.e., to respond to user requests and schedules, to process input data, to store some data for long periods, and to communicate informative results to the users; at times the software will prompt the users to perform manual processes System Design and Engineering in Health Care 235
● Customers: The users who interact with the software and hardware of the system, issue requests, and use the results or forward them to others; there will be other users who are concerned with providing input, system operations, backup, and maintenance The role of a computer is, broadly speaking, the conversion of data into information. Every piece of data must be supplied by a person, by another computer system, or by data collection equipment, as seen in patient monitoring (see Chapter 17). Information that is output is delivered to health care professionals or becomes input to another computer system. In other words, a medical computer system is a module within the overall health care delivery system.
The overall health care system not only determines the need for the computer system (e.g., which data must be processed and which reports must be generated) but also the requirements for the system’s operation (e.g., the degree of reliability and responsiveness to requests for information). Acquisition and operation of a computer system has implications for the organization of an institution. Who controls the information? Who is responsible for the accuracy of the data? How will the system be financed?
The installation of a computer system has sociological consequences as well. The introduction of a new system alters the work routines of health care workers. Furthermore, it may affect the traditional roles of health care workers and the existing relationships among groups of individuals—e.g., between physicians and nurses, between nurses and patients, and between physicians and patients.
Important ethical and legal questions that arise include the confidentiality of patient information, the appropriate role of computers in patient care (especially in medical decision making), and the responsibility of developers and users for ensuring the correct operation of the system (see Chapter 10). Although the technical challenges in system development must be met, organizational factors are crucial determinants of the success of a computer system within the institution. These factors can differ greatly among institutions and can make the transfer of a well-functioning system to another site difficult.
6.1.2 Functions of a Computer System
Computers have been used in every aspect of health care delivery, from the simple processing of business data, to the collection and interpretation of physiological data, to the education of physicians and nurses. Each chapter in Unit II of this book describes an important area for the application of computers in biomedicine. The unique characteristics of each problem area create special requirements for system builders to address.
The motivation for investing in these applications, however, is the computer’s ability to help health professionals in some aspect of information management. We identify eight topics that define the range of basic functions that may be provided by medical computer systems:
1. Data acquisition and presentation
2. Record keeping and access
3. Communication and integration of information
5. Information storage and retrieval
6. Data analysis
7. Decision support