What defines "data quality"?

From page 2:
"Member states shall provide that personal data must be: collected for specified, explicit and legitimate purposes … adequate, relevant and not excessive in relation to the purposes for which they are collected … accurate and, where necessary, kept up to date; every reasonable step must be taken to ensure that data which are inaccurate or incomplete, having regard to the purposes for which they were collected or for which they are further processed, are erased or rectified … kept in a form which permits identification of data subjects for no longer than is necessary for the purposes for which the data were collected ..."

First I wondered, how can transferred personal records be kept minimum for the specific need at hand, while not being "incomplete", but then I read on. Completeness is to encompass, as I understood it: adequate health information so as to not cause a misdiagnosis; adequate credit information so as to not deny a loan or such; and adequate job performance information so as to not cause a loss of potential empoloyement.

(I thought job performance was usually not disseminated by the major corporations, so as to avoid liability.)
This blog post ©reated by Ribonuff on September 22, 2007.