the
use of XP in combination with outside contractors produces a highly questionable outcome,
since the outside contractors may never “jell” with insiders.13 XP requires a
great deal of discipline to prevent projects from becoming unfocused and chaotic. Furthermore,
it is recommended only for small groups of developers (not more than 10),
and it is not advised for mission-critical applications. Since little analysis and design
documentation is produced with XP, there is only code documentation; therefore,
maintenance of large systems developed using XP may be impossible. Also, since
mission-critical business information systems tend to exist for a long time, the utility
of XP as a business information system development methodology is in doubt. Finally,
the methodology requires considerable on-site user input, something that is frequently
difficult to obtain.