Presentation on theme: "Collecting data Chapter 6. What is data? Data is raw facts and figures. In order to process data it has to be collected. The method of collecting data."— Presentation transcript:
Collecting data Chapter 6
What is data? Data is raw facts and figures. In order to process data it has to be collected. The method of collecting data depends upon what it is going to be used for.
Designing a data capture sheet The process of collecting data is called DATA CAPTURE. If a printed form is used to collect data it is called a DATA CAPTURE SHEET.
Designing a data capture sheet The design of a data capture sheet should help the user to collect data efficiently and accurately. It should also enable the data to be entered into a database efficiently and accurately.
Designing a data capture sheet A good design will have: Informative headings. Simple instructions. An easy to use layout. Logical divisions into sections. Been tested before use.
An example of a data capture sheet Informative headings. Simple instructions. An easy to use layout. Logical divisions into sections. Personal data Academic data
Questions Data capture is about getting the answers to specific questions. There are two types of question. These are: –Closed questions –Open-ended questions
Closed questions Closed questions are the easiest to answer and easiest to process. This is because the answers are closed (i.e. they only allow users to enter answers from a specific list of alternatives). Closed questions can produce Yes/No or True/False answers.
Open-ended questions Open-ended questions are the more difficult to answer and less easy to process. This is because the answers are open- ended (i.e. they allow users to enter any answers they wish).
Examples of closed and open- ended questions Closed questions Open-ended questions Only grades from A to U can be entered Only percentages can be entered Written comments can be added
Coding data Because closed questions only allow users to enter answers from a specific list of alternatives it is easy to encode the data before entering it into a database.
Coding data For example, examination grades can be entered a single letters (A, B, C, D, E, F, or U). Another example is gender, which can be entered as M (for male) or F (for female). Individuals can also be given their own code number to identify them (e.g. National Insurance Number).
Coding data Why use codes?They are quicker to enter. It reduces the size of computer files, which increases the speed at which data can be handled. Codes can be unique.
Designing codes Data codes should always: Be the same length – this will add validation (checking that data has been entered correctly). Be easy to use. Not be too short so that additional codes can be added later.
Entering data into a database Once data has been captured, it will need to be entered into a database. This can be done by a variety of methods including: –Keying in using a keyboard –Magnetic Ink Character Recognition (MICR) –Optical Mark Reading (OMR)
Entering data into a database This can also be done by: –Optical Character Recognition (OCR) –Barcode readers –Automatic data capture –Turnaround documents
Keying in data This is the most common form of data entry as it is flexible and can cope with different types of data. However it is time consuming and errors can occur very easily.
Magnetic ink character recognition Magnetic ink character recognition is particularly suited to entering numerical data. It is most commonly used by banks and financial institutions.
Magnetic ink character recognition Magnetic ink characters are printed at the bottom of cheques. They are used by banks to identify the bank a customer banks with, the individual branch where their account is held, and the customers bank account number.
Magnetic ink character recognition Branch codeCheque numberAccount number
Optical mark recognition Optical mark recognition is particularly suited to entering data from closed questions. OMR readers sense marks made on specially designed data capture forms. OMR is a very cheap, easy and quick to handle system of inputting data, but if a user makes a mistake they are difficult to correct.
Optical character recognition Optical character recognition is particularly suited to entering data from open-ended questions. Optical character recognition uses a scanner to input text into the database. It requires special software to convert the scanned image of each letter into an ASCII code, and it often confuses similar shaped letters and numbers (e.g. S and 5, B and 8).
Barcode readers Barcodes are particularly suited to entering coded data, especially if the codes are long and there are lots of alternatives. The lines on a barcode represent numbers, and can be scanned very quickly using a laser scanner.
Automatic data capture Some data can be entered directly into a database by electronic signals. Examples of automatic data capture include: –EPOS (Electronic Point Of Sale) –Remote sensing of traffic flow
Turnaround documents Turnaround documents are produced by computers for use as input documents. Examples of turnaround documents include: –Utility bills (for water, council tax, telephone, gas, and electricity) –Credit card bills
Turnaround documents Turnaround documents are usually printed onto pre-printed forms. They also have a tear off section at the bottom that can be used as an input document when it is presented for payment. The tear off section will often have magnetic ink characters or a barcode to identify the payee.