Evaluation of Information Gathered Electronically
There is a wide array of data available on the internet from a variety of
sites. Not all the information found on the internet is accurate or reliable.
Reliability is the extent to which the information can be depended on to be
accurate.
Reliability has four main attributes:
 Authenticity
 Lack of bias
 Currency
 Relevance
Authenticity is where the information is real or true. This means that you
can rely on the information to be accurate and safe to use.
Lack of bias means that the information is presented in its entirety and not
filtered to focus on one or more outcome. It must also be free from personal
opinions.
Currency means that the information is up to date. Older information might
be out of date and no longer applicable to the present day.
Relevance means the data is appropriate to be used for the intended
application.
Information that is retrieved from the internet or other sources should have
these attributes for it to be deemed reliable and therefore safe to use.
Information should be checked across multiple independent sources to
determine if the information is factually the same and presented in the
same way. Sites where users can edit the content and information are not
reliable sources of information. Especially if there is not a professional or
reputable company fact checking and overseeing the site.
Validation
Validation is an automatic computer check to ensure that the data entered is
sensible and reasonable. It does not check the accuracy of data. The
program looks at the values entered into it and determines if they make
sense based on rules that are programmed into it. It is used to determine if
the data entered is incomplete, inaccurate or unreasonable. If the user enters
a wrong value that still meets the requirements of the rules the data will be
accepted by the program.
For example, if the time is 10:30am but the user enters 10:40am. The
computer will check, and the hour and minutes values are both within
acceptable limits so the computer will accept 10:40am even though it is not
the correct time. If the user enters 26:30am or 10:70am the computer will not
accept the data because the values are outside the expected limits.
Types of Validation
There are several validation checks that can be used to check the data that
is being entered.
Presence Checks: Presence checks are used to check that data has been
entered into a field and that it has not been left blank. For example, a
database storing the names of students would require the surname field for
each student to contain data. However, this check would not ensure that the
correct surname was entered for the student.
Data-type checks: Data-type checks are used to check that an entered
value is of a particular type. When a table in a database is created, each field
is given a data type. Data may be of typed text, memo, number, date/time,
and so on. When data is entered into a specific field, the database will check
to ensure that the data is of the correct type. If not, an error message will be
displayed and the data will have to be re-entered.
Length checks: Length checks are used to check that the number of
characters entered in a field does not exceed the number allocated for the
field or is not fewer than specified. For example, a password, which has to
be 6 or more characters, so A123BC would validate, but AB123 would not.
Range checks: Range checks are used to check whether data is within a
range of possible values. For example, when entering the months of a date
of birth, the range of acceptable numbers lies in the range 1 to 12.
Format checks: Format checks are used to check that the data is entered
in the format specified by the software. For example, a car registration
number should consist of one to three letters followed or preceded by one to
four numbers.
Consistency checks: Consistency checks are checks that ensures that the
data does not contradict other data in the set by checking to see if the current
value is in contradiction with other data, reference data or rules. For example,
a consistency check is often run to ensure a package's shipping date is not
before the order date.
Reasonableness checks: Reasonableness checks are used to compare an
input value with expected reasonable values or testing it based on set rules.
For example, a field that requires “number of passes in CSEC” may flag an
entry of 55 because the rule might say a reasonable range is between 0 and
5.
Verification
Verification is checking that data which has already been entered into a
system matches the data on the source document. For example, going
through a set of values on a sheet and ensuring they match the values
entered into the computer. Verification is usually carried out by humans.
There are two main types of errors that can be found by verification:
 Typographical errors where the user types in the data wrong and there
may be missing or additional characters.
 Transposition errors where the user switches two adjacent characters
in a number or string.
There are two main methods of verification that detects the errors above:
 Double entry: Double entry is where the user enters the data twice and
compares the two copies. This effectively doubles the workload, and as
most people are paid by the hour, it costs more too. If the user enters the
same error twice then the two copies will still match. For example, double
entry is used when inputting a new password to reduce the chance of the
user entering the wrong password. If the user enters the same wrong thing
twice (for example if caps lock is on) the two copies will match and no
error will be detected.
 Proofreading: Proofreading data involves someone checking the data
entered against the original document. It may be the same person who
entered the data or another person. This is also time-consuming and costly.