Information systems depend on people and affect people in many different ways. The impact is often not caused by the technology itself, but by the way people use the technology. Systems can be either machine-centred or human-centred.

Machine-centred systems are designed to simplify what the computer must do at the expense of participants. 

• They assume people will follow procedures that may be confusing in order to get the end result they want. 
• If errors occur in a machine-centred system, they are usually blamed on the participant (operator error) rather than the technology. 
• Machine-centred systems are not always the best systems for participants. 
• People and machines have different strengths and weaknesses. 
• People are good at understanding and coming up with new ideas, whereas machines are good at repetitive tasks.

Human-centred systems are those that make participants’ work as effective and satisfying as possible. 

• They allow people to do their work without wasting time and effort dealing with the information technology. 
• Human-centred systems are user-friendly. 
• In the past, information systems were difficult to use. 
• People needed to understand a programming language to complete the simplest tasks. 
• With developments in technology such as graphical user interfaces, computers are much more user-friendly. 
• However, systems must be developed that pay attention to the work environment and the needs of the participants as well as the information technology.

Work environment

The implementation of a new system may result in major changes in the work environment. 

The Occupational Health and Safety Act requires employers to maintain a safe working environment and protect workers against foreseeable risks. It requires both employers and employees to establish and maintain a safe environment.

Ergonomics refers to the relationship between people and their work environment. 

• It is the process of designing or arranging workplaces, products and systems so that they fit the people who use them. 
• The work environment, and in particular the way a computer is used, can have an affect on the body. 
• The work environment includes the 
• desk, 
• chair, 
• hardware, 
• software, 
• keyboard, 
• work routine and 
• indoor climate. 
• The participant’s relationship with all these factors affects health and efficiency. 
• If computers are being used in the correct way, the working environment is safe and the participant will be able to work at maximum efficiency. 
• Conversely, incorrect use of computers can cause health problems such as eyestrain, headaches, backaches, fatigue, muscle pain and repetitive strain injury (RSI). 
• Carpal tunnel syndrome and tenosynovitis are two common forms of RSI. 
• Carpal tunnel syndrome (CTS) is a pinching of the nerve that passes through the wrist. It is produced by repeating the same small movements many times. Typical symptoms are numbness or burning in the fingers or wrist. CTS can cause permanent nerve damage.
• Tenosynovitis is a narrowing and inflammation of the tendon sheath. It occurs when a repetitive activity exceeds the tendon sheath’s ability to lubricate the tendon. Tenosynovitis causes pain and swelling in the tendons and may cause fingers to lock in one position.

• To help reduce these health problems there have been numerous reports and standards produced that deal with ergonomics and information technology. 

• The Australian Standard AS3590.2 and the Worksafe Australia checklist are standards adopted in Australia.
  These standards can contain slightly conflicting results as they are based on different anthropometric data (body size and shape).
  The general recommendations are outlined below.

Furniture

Furniture needs to be adjusted to suit each person’s body, otherwise problems may develop in the back, neck, shoulders, arms and legs. The desk and chair need to be positioned so that these body parts are used effectively without strain and undue fatigue.

• Desk height should be between 660 mm and 680 mm for a fixed desk, and between 610 mm and 720 mm for an adjustable desk. The depth of the desk should be 900 mm with at least 50 mm for the wrists between the front edge of the desk and the keyboard. This reduces the strain on the forearms when typing.
• Chairs should have an adjustable seat height that ranges from 370 to 520 mm from the floor. This allows a clearance of 200 mm between the seat and the desk. An adjustable backrest should be between 170 to 250 mm above the seat and fit snugly into the small of the back. The seat should be flat, well padded and slanted slightly backwards. This forces the participant to lean against the backrest and maintain good posture.

Information technology

Hardware and its placement are an important ergonomic factor. The system unit bought as a tower or mini-tower can be placed away from the screen, keyboard and mouse to provide increased desk space. The recommendations for the screen, keyboard and mouse are outlined below.

• The screen should be about an arm’s length away with the user looking down on the screen. It should also be between 15 and 30 degrees below eye level and adjusted so that it is at right angles to the line of sight. Adjustments of angle, brightness and contrast should be possible to cater for individual differences.
• The keyboard must be detachable and positioned so that the forearms are parallel to the floor. The angle of the keyboard relative to the desk should be between 5 and 18 degrees with the keys requiring a minimum of pressure.
• The mouse must fit the hand and be easily moved. The button should require a minimum of pressure. The sensitivity of the mouse should be easily adjusted to suit the operator.

Software should be ergonomically designed to make the user feel relaxed and comfortable. A range of software has been developed to meet the needs of everybody, depending on their level of software understanding and their task requirements. It should be designed to minimise movement, improve speed and be easy to use. If the software is easy to understand and use, it is user-friendly. Most people find the GUI (graphical user interface) environment to be user friendly.

Environmental factors

The work environment is affected by environmental factors such as lighting, indoor climate and noise.

• Incorrect lighting can cause eyestrain, double vision and headaches, and reduce visual powers. Lighting needs to be uniform and bright enough for all text to be read easily on the screen, keyboard and paper.All parts of the work environment should have non-reflective surfaces to minimise glare. Glare is reduced by using shades on windows, diffusers on overhead lighting and antiglare filters on screens.
• If the climate of a room is uncomfortable, it can cause weariness, sleepiness, loss of performance and increased errors. The comfortable temperature range varies depending on many factors. For a clothed and resting person, the temperature should range between 20 and 23°C. If the relative humidity of the air is between 30 and 70 per cent it will not create any discomfort. Air movements such as draughts are unpleasant if they exceed 0.2 m/s.
• Excessive noise in the work environment can be a significant distraction. Noise levels should not exceed 55 decibels, as this makes communication with others difficult and can affect concentration. Protection from noise can be obtained by sound-insulating a room, enclosing the source of the noise with sound-absorbing materials, or by using headphones, ear plugs and soft music.