The accuracy of your calculations are only as good as the accuracy of your data. By applying data validation you can significantly reduce the risk of incorrect data creeping into your spreadsheets. The parameters and rules that you set can prevent you, or anyone else, from inputting incorrect or illogical data.
Data validation
To apply data validation first highlight the range of cells you wish to set parameters for, then click Data > Data Validation. This will open up the following window:
