Learn Finnish: Täällä laatua ei mitata tarkasti. - Here, the quality is not measured carefully.

The present passive negative is made by using the negative word ei alongside the passive "connegative" form. For verb type 4 words like mitata (to measure), this is very easy: the passive connegative looks exactly like the dictionary form! You just drop the -an from the positive passive (mitataan) to get mitata.

Why is the word laatu (quality) in the partitive case (laatua)?

In Finnish, the object of a negative sentence must always be in the partitive case. Because the action here is not happening (ei mitata), the basic word laatu has to take the partitive ending to become laatua.

I learned that "I measure" is minä mittaan (with two 't's). Why does mitata only have one 't' here?

This is due to consonant gradation. Verb type 4 words have the "strong" grade in their active personal forms (like mittaan, mittaat). However, the passive forms—both the positive mitataan and the negative ei mitata—use the "weak" grade, which only has one t. This happens to match the dictionary form, mitata.

How does tarkasti translate to "carefully" or "accurately"?