Systems and Information Quality

Decision Support Systems

Information Systems

What is the difference between an information system and a system in general? System

A group of interacting components with a purpose.

Every system has a boundary Closed systems Open systems

Your body Metropolitan area transportation system. Systems often incorporate feedback.

Information Systems

Information systems Is a system whose purpose is to store,

process and communicate information.

DSS As Information Systems

How does a decision support system differ from an information system in general? An information system is a DSS, but can reach

some conclusions that do not apply to all types of information systems.

Usually uses one or more data stores Does not update the databases it used as

external information sources Communicates with the decision maker The decision maker supplies the DSS with

specific information defining the decision to be made.

Information and Information Quality

Difference between data and information Data is what the information systems

department creates, stores and provides. Information is anything that reduces

uncertainty. Information is data in its business context.

Creating Information From Data

The two fundamental operations involved in turning data into information.

Comparing one data element with another We compare the starting time of a movie with our

earliest possible arrival, the projected rate of return on developing motorcycle CD players, etc.

Performing calculations on data We calculate our earliest possible arrival time at the

movie theater from the ending time of dinner and expected travel time. We compute the expected profitability of the motorcycle CD player from projected costs and revenues.

What can go wrong in the process?

The Affect of Computers on Information Quality The eleven factors that define information

quality, and the affects of computers:

The Affect of Computers on Information Quality The eleven factors that define information

quality, and the affects of computers:

1 Relevance Applies to the task being performed Relevance is not an all or nothing situation A data requirements study should be on of

the first parts of any DSS project

The Affect of Computers on Information Quality –Cont’d2 Correctness

Some correctness situations are absolute, where the data elements have no error tolerance.

A phone number is either correct or it isn’t A catalogue number either refers to size 9B black

shoes or it doesn’t Other data elements are still correct if they are

somewhat off from their actual value. = 3.14159 Misspelling my name Caren Reeves instead of

Karen Reaves. It’s still correct because it refers to me, but it is

inaccurate. What’s the number one reason for incorrect data?

The Affect of Computers on Information Quality –Cont’d

3 Accuracy The accuracy of a data element is a measure

of how close it is to its real world value. The accuracy information quality factor

allows for some errors in the underlying data Knowing the outdoor temperature to within 5

degree Fahrenheit or so is sufficient to guide our choice of clothing

Most automobile odometers are accurate to about 2 percent.

The Affect of Computers on Information Quality –Cont’d

4 Precision The precision of a data element is the maximum

accuracy that can be represented by the way a data element is stored in a computer and presented to its users. Corporate earnings per share are usually stated to

the nearest cent, even when the input data can provide correct tenths or hundredths of a cent.

Graphs are seldom highly precise Color coding requires classifying data into a few

ranges

The Affect of Computers on Information Quality –Cont’d

5 Completeness Completeness means that it includes all the

necessary elements for the decision that is to be made and that each element is based on all relevant factors

The Affect of Computers on Information Quality –Cont’d

6 Timeliness Refers to relationships among three items:

The time that information is needed The time that information is made available The time that its underlying data was obtained

Information must reflect up-to-date data Information must be available in time for its

intended use

The Affect of Computers on Information Quality –Cont’d

7 Usability How quickly and easily its intended users can

figure out what they need to know from what they see.

High quality information is presented in a usable format.

The Affect of Computers on Information Quality –Cont’d

8 Accessibility This means that authorized people can obtain

it quickly, with an acceptable level fo effort, from places in which they are expected to be when they need it.

9 Conformity to expectations Is how well the information’s processing,

timeliness, and so on match what this person expects.

The Affect of Computers on Information Quality –Cont’d

10 Consistency Means that all data elements that contribute to

an information item, or a set of related items, are based on the same assumptions, definitions time period, and other factors

11 Cost of information The cost of anything is a measure of the

resources, translated into financial terms, that an organization must expend to obtain it.