die Vollständigkeit
completeness
The state of something being complete, with no parts or information missing.
Bitte überprüfen Sie die Dokumente vor der Abgabe auf Vollständigkeit.
Please check the documents for completeness before submitting them.

completeness
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completeness
The state of something being complete, with no parts or information missing.
Bitte überprüfen Sie die Dokumente vor der Abgabe auf Vollständigkeit.
Please check the documents for completeness before submitting them.

'Vollständigkeit' (completeness) is a noun derived from the adjective 'vollständig' (complete). This, in turn, is made up of 'voll' (full) and 'ständig' (constant). The ending '-keit' turns it into an abstract noun that describes the state of being complete.
Die Vollständigkeit seiner Sammlung war beeindruckend.
The completeness of his collection was impressive.
This noun is often used in formal or official contexts. Typical verbs are 'auf Vollständigkeit prüfen' (to check for completeness) or 'auf Vollständigkeit kontrollieren' (to check for completeness). A common phrase is also 'keinen Anspruch auf Vollständigkeit erheben' (to make no claim to completeness).
Die eingereichten Unterlagen werden nun auf ihre Vollständigkeit geprüft.
The submitted documents are now being checked for completeness.
The phrase 'der Vollständigkeit halber' (for completeness) is a fixed expression. You use it to signal that you are adding a piece of information in order to cover a topic completely. In a sentence, the phrase often appears at the beginning (position 1) or in the middle field.
Der Vollständigkeit halber möchte ich noch einen weiteren Punkt erwähnen.
For completeness, I would like to mention one more point.
integrity
'die Vollständigkeit' and 'die Integrität' can both have to do with something being whole and undamaged. 'Vollständigkeit' mainly asks: Is anything missing? This fits well with lists, documents, or information. 'Integrität' is more about whether a system, structure, or file is unchanged, intact, and reliable. Learners may confuse the words because being 'complete' is sometimes part of being 'intact'. As a practical guide: when parts are missing, you usually say 'Vollständigkeit'; when talking about the intact condition or protection of a system, 'Integrität' is more likely.

Vor dem Versand prüft Lena die Vollständigkeit der Bewerbungsunterlagen.
Before sending them, Lena checks that the application documents are complete.
Das Programm kontrolliert, ob die Integrität der gespeicherten Daten noch sicher ist.
The program checks whether the integrity of the stored data is still secure.