Term 2, 2011 Week 6

CONTENTS Validating data Formats and conventions – Text – Numerical information – Graphics Testing techniques – Completeness testing – Reliability testing – Presentation testing – Functionality testing – Accessibility testing – Timeliness

As we previously learned, inaccurate data comes from measurement & human error. Before using a data set as a basis for a graphic representation, it should be checked for illegal data types, for reasonableness, correctness & that it falls within an applicable range.

There are 4 main types of electronic validation: – Range checking Checking to ensure that data falls within a particular range (e.g. IF statement is used to return a value if the criteria is not met). – Existence checking Identifies whether or not a specified value is present (e.g. A total figure may not show until all data is entered, however a lookup formula can be used to check existence). – Data-type checking Used to ensure that the data is of the correct type (e.g. Check to ensure mobile phone numbers are entered as integers, not decimals. Alignment of data also assists data-type checking). – Restricted data entry To ensure that the data entered is valid, you can restrict data entry (e.g. Drop down lists restrict the user to only entering one of a finite amount of choices).

When we create a solution, we should follow commonly used formats & conventions to improve effectiveness.

DataFormats and conventions Text Use one space after all punctuation. Ensure the capitalisation of headings and names is consistent. Maintain consistency with margins, page numbering, spacing and indentation. Font> different sizes should be used sparingly, serif/sans-serif for different parts of the text. Numerical information Money values should have two decimal places or none. Numbers are right aligned in columns. Align decimal points. Graphics Graphs and charts have titles. Use titles to identify the purpose of the graphic representation. Include the unit of measurement on the relevant axis. A full list of formats and conventions is available in your text book page 31-32).

It is important to check that what you are trying to produce meets the specified need & fulfils the required purpose.

Completeness testing Does the user need to perform their own calculations or source information from somewhere else? If the answer is yes, then the solution is incomplete.

Reliability testing Has the data been verified against the primary or another secondary source? Is the source reliable?

Presentation testing Have the appropriate formats & conventions been applied? Is the information consistent?

Functionality testing Does the solution meet the user’s required needs? When testing the function of a spreadsheet, it is important to test every formula & function to ensure that they all do what we intend them to. A test plan is a method for recording the tests to be executed and the results of the test. Usually includes the type of test, what test data will be used, what results are expected & the end results.

Accessibility testing Is the information clearly presented? Are red/green & blue/brown used together? – Such combinations shouldn’t be used as they are difficult for colour blind people to read. Is the font too small?

Timeliness Is the data current? Has it been processed soon after collection?

Relevance testing When checking relevance: – Does the solution match the user’s search for information?

Usability testing Is there a lot of scrolling on pages? Are worksheets clearly labelled with meaningful & relevant names? Are validation alerts clear & helpful? Does the user have the ability to delete formulas or edit ‘fixed’ data? Does the spreadsheet use adequate protection?

Communication of message Is the information clear and obvious? Will the user be puzzled by what they are presented?

Testing graphic representations To specifically test the quality of onscreen information that is represented in graphic form, ask the following questions. – Does the graphic representation depict the information required and the intended purpose? – Is the overall look and tone of the graphic representation appropriate to its intended purpose? – Is the graphic representation accurate? This is, has the data source been validated and verified? – Is there anything that is misleading, confusing or unclear? – Does the value axis scale for a column chart start at zero? – Is the numerical scale of the value axis identified (i.e. thousands, millions etc.) (A full list is available p in your text book).