1. DATA COLLECTION
Data Collection
Data Verification and Validation

2. Data Collection
Before data is input into a computer it needs to be collected. This can be done in several ways:
 Data Capture Forms. Answers to questions are filled in by people on specially-prepared forms. These forms are called data capture forms (questionnaires) and need to be carefully designed.
These answers will then need to be typed into a computer for analysing. This is called transcribing the data.
Example : A membership form for a club may need to be filled in by a pupil wanting to join.
Data preparation is the process of transferring the data into a form which can be processed by a computer.
Some forms can be read automatically by special machines (OMR, OCR, MICR)....

3. OCR
OCR stands for Optical Character Recognition. OCR is used for reading characters from paper, using scanners, and inputting them into a computer.
The shapes of different characters are detected by shining light on them, and sensing the patterns of reflected light. Each pattern is compared with a set of stored patterns until the closest match is found.
Scanners were originally designed to scan pictures but they can also be used to scan text into a word processor.
OCR can save a lot of typing if you need to enter a printed document onto a word processor!Advantage:
OCR is faster than typing!
Disadvantage:
You need to buy a scanner and OCR software.
It is not completely accurate, and text would need proof-reading afterwards.

4. OMR OMR stands for Optical Mark Recognition.
OMR uses light to detect the position of black marks on white paper.
The documents to be read have empty boxes pre-printed onto them. The user makes pencil or ink marks in the appropriate boxes.
Sometimes also called mark sensing.
Example applications :
1) School registration sheets may be read by an OMR reader.
2) A multiple-choice examination. Pupils answer questions by making a mark in an appropriate box. All the papers are marked by a computer where the answer sheets are input using an OMR reader.

5. M.I.C.R. MICR stands for Magnetic Ink Character Recognition.
Characters are printed using a special magnetic ink which contains iron oxide. As the document passes into the M.I.C.R. reader, the ink is magnetised, so that the shapes of the characters can be recognised electronically.
The characters have to be printed in a special font, the one used in Britain has only 14 possible characters :-
Advantages :
Documents are difficult to forge.
Documents can still be read after being written on, folded, spilt on etc...
Disadvantages :
M.I.C.R. readers and encoders are expensive.
The system can only accept a few characters.

6. Bar Codes
A bar code is a set of parallel printed lines of differing thicknesses which are used to store coded information about an item.
Bar codes are read using a Bar Code Reader, which can be in the form of a hand-held ‘wand’ or a stationary laser scanner over which the bar code is passed.
This method of data entry is used in big shops and supermarkets and in libraries.
Advantages
a fast method of data entry
eliminates possible human error
Disadvantages
scratched or crumpled barcodes may cause problems

7. Magnetic Strip
A magnetic strip (or stripe) is a short length of magnetic tape sealed onto the surface or embedded in a ticket or card. The stripe usually contains information to identify the ticket or card or its user.
To swipe a card with a magnetic stripe means to move the card through a card reader so that the stripe can be read.
Examples :
1.Credit / Debit Cards The card stores details about the user's account and bank.
Credit card - the money is given to you and you pay it back later. Debit card - the money is deducted directly from your bank account.
2.Phone cards
The card stores the number of units left.

8. Verification and Validation
One method of avoiding transcription errors (when the data is entered into the computer) is verification. The data is entered twice by two different people and the computer will only accept the data if the two versions are identical.

9. Data Validation
Data validation checks that the data is sensible before it is processed. Methods used for validation are...
Range check This checks that the data lies within a specified range of values. Eg the month of a person's DOB should lie between 1 and 12
Presence check This checks that important data is actually there and has not been missed out.
Type check A check that data is of the right type.  Eg number, text etc
Length check Checks that fields have the correct number of characters. Eg A bank account number may always be 10 digits long.
Check digits Used for numerical data. An extra digit is added to a number which is calculated from the other digits. The computer checks this calculation when data is entered. Eg The ISBN number on a book. The last digit is a check digit.
Batch totals This checks for missing records. Numerical fields may be added together for all records in a batch. The batch total is entered and the computer checks that the total is correct.