efficient/effective

efficient refers to improvement in utilization (use) of time, money, resources, labour/manpower, etc. It is usually represented quantatively, i.e. measurable values/numbers/figures.

effective refers to complete a task or a mission as planned or as intended. It is usually represented qualitatively, i.e. the process, procedure, method, execution, delivery, schedule, usage of available resources, management, etc.

He completed the project efficiently generally means he finish the job on time and/or used the least among of available resources.

He completed the project effectively generally means he manage the various elements/aspects, such as staff/people, materials/products, customers, marketing, in good and smooth delivery according to the target. Of cause this include time and money spent.

So usually effective may include efficient + other factors.

efficient解效率，顧名思義係等同數學上嘅比率(ratio)，通常以百分比做單位，例如一日八個鐘可以完成工作數量。effective解作有效，但就比較抽象，可以針對efficient作准，例如more efficient就more effective。