Инициатива — сильная сторона сотрудника.

In Russian, a dash is often used in a sentence where one noun phrase is being identified as another noun phrase, especially in the present tense, where есть is usually omitted.

So this sentence is structurally like:

• Инициатива — сильная сторона сотрудника.
• literally: Initiative — [the] strong side of the employee.

In English, we would usually use is, but in Russian the present-tense to be is normally left out:

• Инициатива есть сильная сторона сотрудника — possible in some special contexts, but not the normal phrasing.

The dash helps show the relationship clearly: X = Y.

Because in Russian, the verb to be in the present tense is usually omitted.

So:

• Инициатива — сильная сторона сотрудника.

means:

• Initiative is the employee’s strong point.

This is completely normal Russian.
Russian often leaves out is / am / are in present-tense statements like this:

• Он врач. = He is a doctor.
• Москва — столица России. = Moscow is the capital of Russia.

Because сотрудника depends on сторона in the sense of possession or relation.

The phrase сильная сторона сотрудника means:

• the employee’s strong side
• or more naturally, the employee’s strong point / strength

Here:

• сторона = side
• сотрудника = of the employee

So сотрудника is genitive singular of сотрудник.

This is a very common pattern in Russian:

• книга студента = the student’s book
• дом брата = the brother’s house
• сильная сторона сотрудника = the employee’s strong point

Because it agrees with сторона, which is a feminine noun.

Russian adjectives must agree with the noun they describe in:

• gender
• number
• case

Here:

• сторона is feminine singular nominative
• so the adjective must also be feminine singular nominative: сильная

Compare:

• сильный сотрудник = a strong employee
• сильная сторона = a strong side / strong point
• сильное качество = a strong quality

It is both understandable literally and very commonly used idiomatically.

Literally, сильная сторона means strong side.
But in real usage, it usually means:

• strong point
• strength
• area of strength

So in this sentence, a very natural English equivalent is:

• Initiative is the employee’s strong point.
• Initiative is one of the employee’s strengths.

This phrase is very common in job interviews, evaluations, CVs, and business language.

Because this is a sentence of identification/equation with no expressed present-tense verb.

In this pattern, the main noun phrases are often in the nominative:

• Инициатива = nominative
• сильная сторона = nominative

The genitive сотрудника is only inside the second phrase, modifying сторона.

A useful comparison:

• Инициатива — сильная сторона сотрудника.
  = Initiative is the employee’s strong point.

But if you use a verb like являться, the predicate is usually instrumental:

• Инициатива является сильной стороной сотрудника.

So:

• with a dash and no verb: often nominative
• with являться: instrumental

Yes, absolutely.

That version is grammatically correct and means the same thing. It is just more formal or bookish.

Compare:

• Инициатива — сильная сторона сотрудника.
  more neutral, compact, natural in many contexts

• Инициатива является сильной стороной сотрудника.
  more formal, heavier, often used in written or official language

Notice that after является, сильная сторона changes to instrumental:

• сильной стороной

Yes. Russian word order is flexible, and changing it can shift emphasis.

For example:

• Инициатива — сильная сторона сотрудника.
  Focuses first on initiative.

• Сильная сторона сотрудника — инициатива.
  Focuses first on the employee’s strong point, then tells you what it is.

Both are correct. The difference is mostly about emphasis and information flow, not core meaning.

Сотрудник most commonly means:

• employee
• staff member
• worker in an organization

It is a fairly neutral and common word in professional contexts.

Depending on context, it can sometimes also mean:

• associate
• colleague
• member of an institution
• even officer/agent in some official contexts

But in this sentence, the natural meaning is employee or staff member.

Most likely as:

• initiative is one of the employee’s strengths
• or initiative is the employee’s strong point

It sounds a bit more evaluative than simply the employee has initiative.

If you only wanted to say the employee has initiative, Russian would more naturally use something like:

• Сотрудник проявляет инициативу. = The employee shows initiative.
• У сотрудника есть инициатива. = The employee has initiative.
  (This is grammatical, though less idiomatic in many contexts than проявляет инициативу.)

So your sentence is more about strength/assessment than just possession.

A helpful stress-marked version is:

• Инициати́ва — си́льная сторона́ сотру́дника.

Approximate pronunciation:

• ee-nee-tsee-a-TEE-va — SEEL-na-ya sta-ra-NA sa-TROOD-nee-ka

A few notes:

• Инициатива has stress on ти́
• сильная has stress on си́ль
• сторона has stress on the last а
• сотрудника has stress on тру́

If you say it naturally, the dash creates a slight pause:

• Инициати́ва — си́льная сторона́ сотру́дника.

Yes. Here инициатива means the abstract quality initiative, not a specific project or proposal.

Russian often uses singular nouns for abstract qualities:

• честность = honesty
• ответственность = responsibility
• инициатива = initiative

So in this sentence, Инициатива means the trait or quality of being proactive.

In another context, инициатива can also mean an initiative in the sense of a proposal or undertaking, but that is not the meaning here.