Yeni proje planına başarı ölçütleri de dahil edilmelidir.

The suffix -meli/-malı expresses necessity or obligation (English “must/should”). Adding -dir at the end gives a neutral, formal tone. So:

• dahil etmek = to include
• dahil edilmek = to be included (passive infinitive)
• dahil edilmelidir = it must be included / it should be included

To make dahil etmek passive, insert -il- (or -n-) between the stem and personal endings:
• Active: dahil etmek
• Passive: dahil edilmek
Then add the necessity suffix -meli and the formal marker -dir → dahil edilmelidir.
We use edil because etmek (“to do/make”) becomes edilmek in passive.

-na (or -a/ -e, by vowel harmony) is the dative case marker, meaning “to” or “into.”

• plan (root)
• -ı (3rd person singular possessive = “its plan”)
• -na (dative = “to/into its”)
  → planı​na = “to the plan.”

Turkish modifiers precede the noun they describe:

1. yeni = new (adjective)
2. proje = project (noun modifying another noun)
3. planı = plan (head noun)
   Add dative → planı​na
   So yeni proje planına = “[into/to] the new project plan.”

The enclitic -de (written de or da) means “also” or “too.” It attaches to the word it emphasizes:
• ölçütleri de = “success criteria too (should be included).”
It’s separate from the word (no space) and follows vowel harmony (after i, we use de).

-i is the definite accusative marker. Even in this passive construction, dahil etmek remains a transitive action that takes an object. Breakdown:

1. ölçüt (stem)
2. -ler (plural) → ölçütler
3. -i (accusative) → ölçütleri
   = “(the) success criteria” as the direct object of “to include.”

Both can translate as “add,” but:
• dahil etmek = to include something within a set or group (e.g. include success criteria in the plan).
• eklemek = to append or attach something new, often at the end (e.g. add an appendix).
Use dahil etmek when you want to fold something into an existing structure.

In active voice you need a clear subject. For example:
“Yeni proje planına başarı ölçütlerini de dahil etmeliyiz.”
Literally: “We must also include the success criteria in the new project plan.”