Topic 1: Data, Information and Knowledge Learning Outcomes Learning Outcomes What data, information and knowledge is What data, information and knowledge is The difference between data, information and knowledge The difference between data, information and knowledge How computers store and interpret data How computers store and interpret data Types of encoding Types of encoding What are value judgements and what problems can they pose What are value judgements and what problems can they pose

Data, Information and Knowledge Computers are machines that process data. Information systems perform processes on this data and output it as information. Individuals with knowledge of the wider context can then use this information to draw conclusions and make decisions. Computers are machines that process data. Information systems perform processes on this data and output it as information. Individuals with knowledge of the wider context can then use this information to draw conclusions and make decisions. But what is the difference between data, information and knowledge? But what is the difference between data, information and knowledge?

Data Data is a collection of raw facts (datum singular) Data is a collection of raw facts (datum singular) the computer understands only this data Fred, Joe, Fred, Joe, 27,15 27,15 If asked about data you must provide more than one item! If asked about data you must provide more than one item!

Information Information = data + context (or processing) Information = data + context (or processing) From the last slide “Fred is my dog’s name”, “Joe is my friend” From the last slide “Fred is my dog’s name”, “Joe is my friend” 27/30 is my exam result 27/30 is my exam result 15 is my age 15 is my age

Knowledge Is applying rules to information Is applying rules to information 27/30 your exam result your teacher then applies their knowledge and makes a judgement about your progress 27/30 your exam result your teacher then applies their knowledge and makes a judgement about your progress A Doctor given a set of blood pressure readings: what is the data, information and knowledge here? A Doctor given a set of blood pressure readings: what is the data, information and knowledge here?

Example This data is stored on computer (in binary format) 130/80 This is the information that is displayed Blood Pressure is: 140/80 The doctor applies his/her knowledge to this information and decide if a patient is at risk or not. Fortunately this patient is in the normal range so BP is OK The doctor applies his/her knowledge to this information and decide if a patient is at risk or not. Fortunately this patient is in the normal range so BP is OK

ENCODING DATA If large amounts of data are being processed, data items are often replaced by codes e.g. the items in a supermarket have bar codes on them representing the product number. This code is used to enter data into the computer. If details need to be printed out then more meaningful information will be given. If large amounts of data are being processed, data items are often replaced by codes e.g. the items in a supermarket have bar codes on them representing the product number. This code is used to enter data into the computer. If details need to be printed out then more meaningful information will be given.

Example At the supermarket checkout, the bar code is scanned to enter data in the form of a product number, but when the receipt is printed out the name of the product is displayed. At the supermarket checkout, the bar code is scanned to enter data in the form of a product number, but when the receipt is printed out the name of the product is displayed. Encoding data means converting information or data into a code for processing. Decoding data means converting it back into a form that can be understood.

Common codes Male and Female M and F International Standard Book Number (ISBN) Bank sort codes Date of Birth Codes are used because: they are often short and easy to enter they take up less storage space on disk they are easier to validate

Advantages Codes are used because: they are often short and easy to enter less chance of error they take up less storage space on disk (for the exam you must say in computer’s memory or hard disk drive) Consistency because of pre-established codes (think airports, MAN, LHR)

Limitations 1: Reduction of Accuracy The data can be “coarsened” this means the results may less accurate as they have to fit into pre-defined categories. The data can be “coarsened” this means the results may less accurate as they have to fit into pre-defined categories. E.g. eye colour was limited to blue, brown, green, grey what do people with blue/grey eyes select? E.g. eye colour was limited to blue, brown, green, grey what do people with blue/grey eyes select?

Limitations 2: Coding Value Judgements A value judgement is a matter of opinion rather than fact. A value judgement is a matter of opinion rather than fact. The problem with a value-judgement is that there isn’t a single correct value. The problem with a value-judgement is that there isn’t a single correct value. The value depends on opinion and may differ from someone else’s opinion. The value depends on opinion and may differ from someone else’s opinion.

Examples I recycle at 50% of my household waste – this is fact. I recycle at 50% of my household waste – this is fact. I recycle a lot of my household waste – this depends on someone’s classification of a lot. I recycle a lot of my household waste – this depends on someone’s classification of a lot. An environmentalist who recycles 80% of their waste may consider 50% not a lot! Someone who has never recycled may consider 50% a massive amount. An environmentalist who recycles 80% of their waste may consider 50% not a lot! Someone who has never recycled may consider 50% a massive amount.

Other value judgements young, middle-aged, old young, middle-aged, old tall, average, short tall, average, short often, not very often, never often, not very often, never When you need to collect data you need and agreed encoding system you will need to qualify value judgements.

Coding for Computers Computers need to know which encoding system has been used to encode data, MP3, JPEG, WAV Computers need to know which encoding system has been used to encode data, MP3, JPEG, WAV ASCII is a method of converting ones and zeros to characters. ASCII is a method of converting ones and zeros to characters.