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Data preparation and data capturing. Topics Covered: Data preparation Data capturing Data verification and validation Data editing. Data preparation:
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Topics Covered: Data preparation Data capturing Data verification and validation Data editing
Data preparation: Data preparation involves checking or logging the data in, checking the data for accuracy, entering the data in the computer, transforming the data and developing and documenting a database structure that integrates the various measures. • Logging the data:- The data may come from a number of different sources at different times. A data base may be setup that enables the user at anytime to know what data is in and what is still needed.
Checking the data for accuracy: As soon as the data is received it is screened for accuracy in some cases it leads to previous collection to clarify any problems or errors. • Developing a database structure: The structure in which the user wants to store the data for the study so that it can be accessed in subsequent data analysis. Generally the two options can be used for storing data on computer • Data base programmes • Statistical programmes
Entering the data in computer: There are a wide variety of ways to enter the data into the computer for analysis. The simplest way is to type the data directly. In order to assure a high level of data accuracy special programmes can be used that allow checks procedure to reduce the data entry errors. Data transformations: Once the data have been entered it is necessary to transform the raw data into valuables that are usable in the analysis.
Data capturing: It is a method of actually collecting the data from various resources which may be manual or in computers data may be captured by using different types of input devices. Input devices may be online or offline. Online data entry: It involves devices such as terminals, which are connected directly to the computer. On line processing is also called as direct processing. The data may be keyed in directly by the use of keyboard or other data collection and recording devices. Using these input data appropriate records may be quickly updated. Also the access to and retrieval of any record is quick and direct.
Offline data entry: It involves devices through which data is recorded on some media such as magnetic tapes or magnetic disks and then entered into computer later. Since data entry is done by data entry operators and their speed is less than data processing so in most applications data entry is done offline. This saves computer time. The major forms of permanent storage are cards, tapes and disks. There are offline data entry devices for each type. • Key to card: Oldest offline data entry devices. It allows an operator to convert data recorded on paper to punched cards.
Key to tape: A key to tape device is designed to record keyed data directly onto magnetic tape. • Key to floppy: These data entry machines were introduced as low cost data recording systems. They are used to store data directly on flexible disks, called floppies that are inexpensive and reusable. • Key to disk: Key to disk devices are used as recording stations in systems where data from different points has to be recorded for processing at one point.
Data verification and validation: It is a process in which data entered in computer is checked for correct type and correct value. This validation procedure can be performed on the individual record or on group of records. Also the process of data validation can be performed at different levels of data during output process. The different validation checks that can be applied in a system are as follows: • Completeness check:- The check ensures that all the fields in the record are entered in a proper sequence. In a multiple record check programme verification is performed after a number of specified records and if any of the error is detected the entire group of records is rejected
Consistency check:- It refers to the comparison of one type of data with other if the second one is completely dependent on the first data. This check ensures that if the same data is available at two places then data should be completely same at both the places. • Sequence check: This check is used to verify the data which has been recorded is in a sequence so as to check the correctness of the sequential order of the data before processing the data. If the key field value of the records is not in a sequence then the process of sorting is done before actually processing of the data.
Duplicacy check: This check is used to find out the duplicate records. Duplicate records are identified and removed to make the data consistent and to save the time of computer system.
Data editing: It is a process which is performed to represent the data which is stored in the memory. By representation of data means that the data should be given to the user after all the processing in such a way that it contains no unnecessary information. Some of the editing processes are as follows: • Insertion of decimal point: Data editing can be applied to indicate the place of decimal point on the screen and the number of digits after the decimal point.
Currency symbol: It is used to insert the currency symbol before or after the numeric data. It can be a dollar symbol $ or the sign of rupees. • Data justification: It is used to represent the data in some predefined justification order. e.g. character data is right aligned. This utility of data justification is used to align the data in some predefined width of a cell. • Insertion of comma: Business amounts are generally represented by separating the digits by commas. By default computer software does not include in numeric figures but commas can always be inserted under the process of editing.
