Although / even though + clause

Although and even though admit one fact and then say something that contrasts with it: the second fact is true in spite of the first. After them you need a full clause with its own subject and verb.

Although / Even though + subject + verb, main clause

• Although the video looks real, it was created by a computer.
• Even though the newspaper apologized, many readers cancelled their subscriptions.
• Few people read the correction, although it was printed on the front page.

While / whereas: two facts in contrast

While and whereas compare two things that are different: two sources, two groups, two periods. Nothing is unexpected here — the sentence simply balances one fact against the other.

clause, + while / whereas + clause

• Older readers prefer print, whereas younger readers get their news online.
• The local paper reported the facts, while the blog offered only opinions.
• Whereas the first article names its sources, the second does not.

Although shows that the second fact is surprising; whereas only shows that two facts are different. At the start of a sentence, while can also mean although: While the data is useful, it is incomplete.