Lertap 5 is an Excel "app". Data may be entered directly into an Excel spreadsheet via the computer's keyboard. Data may also be imported by reading files produced by, for example, bubble sheet scanners.
Excel has very good facilities for data "snooping", providing handy tools, such as "Filter" and "Pivot tables", for looking at data quality. Lertap has some too -- see this little discussion with examples.
Lertap 5's output, its numerous tables and charts, are all nested in well-formatted Excel worksheets. Print them easily. Save them to PDFs if you want. Add more charts and graphs readily. Reformat and re-colour them when wanted.
Use of Excel for data input, output, and manipulation results in an "all in one" application. This is worth noting as a great number of other item analysis programs require that data be prepared by using another application -- some even make it necessary to use an external application (such as a word processor) to read their output.
An "all-in-one" app is considerably more convenient and very often substantially easier to use.
Data analysts frequently want to use more than one software system in order to look at their data in other ways. Excel worksheets have become a "lingua franca", a common "language", facilitating data sharing among a variety of "apps", such as SPSS and SAS. The factor analysis routines in these programs will happily look at a Lertap 5-created, Excel-based, matrix of inter-item correlations. Should you be using a program which has not been trained to read Excel worksheets, you might well find that Lertap's Iteman, Xcalibre, and Bilog-MG interfaces will suit your needs well. More information about these interfaces may be found at this topic.
Not an Excel expert? Worry not. Have a gander and a chuckle with Lertap 5's user guide and up and running you'll be. (You may be likely to chuckle as it's not a conventional manual.)