共通 and 同様: A Shared Feature and a Similar Manner
Compare low cost and common concerns with following the same procedure and wishing to show equal respect. Identify a shared feature and a manner applied similarly.
共通 (きょうつう): Shared features and concerns
「二つの案には費用が安いという共通点がある。」 — “The two proposals share the advantage of low cost.” The proposals share low cost as a feature. The English advantage describes that particular common point, not every possible advantage.
「参加者に共通する悩みを最初に聞いた。」 — “We first heard the concerns common to the participants.” Concerns common to participants were heard first. The sentence does not make every concern of every participant identical.
同様 (どうよう): A procedure and equal respect
「前回と同様の手順で作業を進めた。」 — “We followed the same procedure as last time.” The work proceeded by the same procedure as last time. 同様の identifies the manner of the procedure.
「大人と同様に子どもの意見も尊重したい。」 — “I want to respect children's opinions just as I respect adults' opinions.” The speaker wishes to respect children’s opinions just as adults’ opinions. The wish is not a report of respect already shown.
One common point is not complete identity
共通点 identifies a feature several objects share; 同様の手順 identifies a similarly applied procedure. Read the common property and the manner of action separately.
Shared low cost does not make all advantages of the proposals identical. Using the same procedure also does not guarantee identical work results.
What is common or similar in the low-cost 共通点 and 同様の手順?
Show the answer and why
Low cost is the common feature, while 同様 concerns following the same procedure as before. One common feature or similar manner does not establish complete identity of properties or results.