Effective
な adjective
Remember how 効果 means "effect"? Add ~like to that and it's effective!
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
成果主義の給与制度は、良い社員を引き込む最も効果的で公平な方法である。
Performance based salaries are the most effective and fairest ways to attract good workers.