Он оценивает результативность.

Оценивает is the present tense of the imperfective verb оценивать.

• оценивать = to evaluate, to be evaluating, to evaluate in a general/ongoing sense
• оценит = future tense of the perfective verb оценить; it suggests a completed evaluation: he will evaluate / he will make an assessment
• оценивал = past tense: he was evaluating / he evaluated

So Он оценивает результативность presents the action as ongoing, habitual, or simply happening now.

The dictionary form is оценивать.

This is the infinitive.
The form оценивает means:

• he evaluates
• he is evaluating

It is the 3rd person singular present tense form.

A short conjugation:

• я оцениваю — I evaluate
• ты оцениваешь — you evaluate
• он / она оценивает — he / she evaluates
• мы оцениваем — we evaluate
• вы оцениваете — you evaluate
• они оценивают — they evaluate

Because it is the direct object of the verb оценивает, and this verb normally takes the accusative case.

Here, however, результативность is a feminine noun ending in -ость, and nouns of this type have the same form in nominative and accusative singular.

So:

• результативность = nominative singular
• результативность = accusative singular

That is why the word does not visibly change.

Результативность is a fairly formal abstract noun. It means something like:

• effectiveness
• performance
• productivity
• how successful something is in producing results

It is built from результат (result) and refers to the quality of producing results.

In everyday speech, Russians might sometimes choose simpler or more concrete wording depending on context, but результативность is very normal in:

• business
• management
• analytics
• education
• official or professional language

So the sentence sounds somewhat formal or professional.

The stress is:

• Он — usually unstressed in normal speech unless emphasized
• оцЕнивает — stress on Е
• результатИвность — stress on И

So the sentence sounds roughly like:

он оцЕнивает результатИвность

Stress is important in Russian because it affects vowel pronunciation.

Yes, often it could.

Russian frequently omits subject pronouns when the subject is clear from context. So in many situations, you could simply say:

Оценивает результативность.

However, он is kept when:

• you want to be explicit about who is doing it
• you are contrasting him with someone else
• the context is not clear enough without it

So both are possible, but the version with он is perfectly natural.

Yes. Russian word order is more flexible than English word order.

The neutral order here is:

Он оценивает результативность.

But you may also see:

• Результативность он оценивает.
• Оценивает он результативность.

These alternatives usually change focus or emphasis, not the basic meaning.

For example:

• Он оценивает результативность = neutral statement
• Результативность он оценивает = emphasizes effectiveness as the thing being evaluated
• Оценивает он результативность = can sound contrastive or stylistically marked

For learners, the original order is the safest neutral choice.

No. Оценивать is broader than just to grade.

It can mean:

• to assess
• to evaluate
• to estimate
• to judge
• to appraise

Depending on context, it may involve:

• giving a formal rating
• analyzing quality
• making a judgment
• estimating value or effectiveness

So in this sentence, it does not necessarily mean he is assigning a number or grade. It could simply mean he is assessing effectiveness.

Because оценивать follows the pattern of a 1st-conjugation verb in the present tense.

The stem is basically оценива-, and the 3rd person singular ending is -ет:

• оценива + ет = оценивает

This tells you the subject is:

• he
• she
• it

In this sentence, the subject is explicitly он, so it means he evaluates.

Usually результативность is an abstract noun, so it is most commonly used in the singular, much like effectiveness in English.

In most normal contexts, you talk about:

• высокая результативность — high effectiveness
• оценивать результативность — to evaluate effectiveness

A plural form would be unusual and very context-dependent. For a learner, it is best to treat результативность as a mainly singular abstract noun.

The perfective counterpart would usually be:

Он оценит результативность.

Here:

• оценивать = imperfective
• оценить = perfective

The difference is aspect:

• Он оценивает результативность = he is evaluating / he evaluates effectiveness
• Он оценит результативность = he will evaluate effectiveness, with emphasis on the action being completed as a single whole

So if you want the idea of a completed future assessment, use the perfective form.

It can mean both.

Russian present tense often covers both the simple present and the present progressive in English.

So depending on context, Он оценивает результативность could mean:

• He evaluates effectiveness — habitual, general
• He is evaluating effectiveness — right now

The wider context tells you which meaning is intended.