Shadow System - Problems

Problems

When Shadow Data Systems are created by end users whose main area of expertise is something other than software engineering, they are subject to the following problems:

Poorly Designed

Shadow Data Systems often suffer from poor design. Errors may be hard to find, modifications may be difficult, and long-term support may be troublesome.

Not Scalable

Typically, Shadow Data Systems are only used by one or two people. Unless they are developed by experienced programmers, it may be difficult to scale them up to support tens or hundreds of users.

Poorly Documented

Shadow Data Systems are often lack adequate documentation. Knowledge about the system is passed by word-of-mouth and can be confined to a very small number of people. This knowledge is then lost completely if one or two staff members leave.

Untested

Around two thirds of the effort involved in professional software development is expended in testing. Shadow Data Systems undergo much more cursory testing and may have latent errors that only become apparent after a long period of production use.

May Allow Unauthorized Access to Sensitive Information

Shadow Data Systems hold substantial chunks of company data and can include confidential information about customers, suppliers or staff. The access control processes for these systems are often much more lax than for a centralized company database and may not even exist at all. Physically locating sensitive data on desktop or laptop computers can leave an organization very exposed if the computer is stolen.

Easy to Introduce Errors

Data in local databases and spreadsheets can very easily be modified, either intentionally or otherwise. Once changed it can be hard to track what changes have been made and what the original data looked like. Where the system manipulates the data it can introduce more subtle errors that remain completely undetected for long periods.

Back Up

Shadow systems existing on a single computer are often not regularly backed up. It is best to have these systems on a computer that is regularly backed up or on a server.

Several Versions of the Truth

There may be many different Shadow Systems within an organization reporting against the same data. Each one may add filters and manipulate the data in different ways. This can lead to apparent inconsistencies in their output. Where two Shadow Systems disagree, either or both of them may be wrong.