Learn Hardcore Turkish: Kalibrasyon yapılmadan veri güvenilir olmaz. - Without calibration, data is not reliable.

The ending -madan is a negative converb (zarf-fiil) meaning “without doing X.” It attaches to the verb stem (here yapıl-) and forms an adverbial clause. So Kalibrasyon yapılmadan literally means “without calibration being done.”

Why is yapılmadan in the passive voice? Could we say yapmadan instead?

Using the passive yapılmak (“to be done”) makes the statement general—anyone performing the calibration or the act itself is implied.

Kalibrasyon yapılmadan = “without calibration being carried out (by someone).”
If you said Kalibrasyon yapmadan, it would sound like “without you (or I) calibrating,” which is more personal and less formal in technical contexts.

Why is there no article before veri (“data”)?

Turkish does not have indefinite articles (“a,” “an”) and uses a bare noun for both singular and plural senses unless specificity or plurality is needed. Here veri can mean “the data” or “data in general.”

What does güvenilir mean, and why is it used with olmaz?

güvenilir is an adjective meaning “reliable” or “trustworthy” (literally “can be trusted”).
olmaz is the negative of olmak (“to be”). Combined, güvenilir olmaz = “is not reliable.”

Why not say veri güvenilmez instead of veri güvenilir olmaz?

güvenilmez is the passive form of güvenmek (“to trust”), so veri güvenilmez would grammatically mean “the data is not trusted,” which is technically okay but less idiomatic.
güvenilir olmaz focuses on the property “reliable/not reliable,” which is more natural when assessing data quality.

Could we use a conditional -sa form instead of -madan? For example: Kalibrasyon yapılmazsa veri güvenilir olmaz?

Yes.

Kalibrasyon yapılmazsa veri güvenilir olmaz = “If calibration isn’t done, the data won’t be reliable.”
-madan is slightly more concise and emphasizes “without doing X,” but both convey the same logical relationship.

Can we pluralize veri and say veriler güvenilir olmaz?

Technically you can say Veriler güvenilir olmaz (“The data are not reliable”), but in Turkish veri often functions as a mass noun (like English “data”). Pluralizing it is possible when you mean discrete data sets, but it’s not required for general statements.

How does word order work in this sentence—why is yapılmadan at the beginning and olmaz at the end?

Turkish is generally Subject–Object–Verb (SOV). Adverbial clauses (like our -madan phrase) precede the main clause. The main clause here is veri güvenilir olmaz, ending with the verb olmaz, which is typical: all descriptive elements come before the final verb.

What’s the difference between güvenli and güvenilir? Why choose one over the other?

güvenli means “safe” or “secure” (e.g. güvenli bölge = “safe zone”).
güvenilir means “reliable” or “trustworthy” (e.g. güvenilir kaynak = “a trustworthy source”).
Since we’re judging data quality (reliability), güvenilir is the correct adjective.