Performance Management: Is for the company better to set short-term or long-term targets? Do you have any other opinion?

Setting long or short term targets depends mostly depend upon the company and nature of product or service it renders. Generally,  it is better to go for a short term to measure their performance or other option is to can go for a period-period which means once the performance is judge for a particular period, lets say during peak period, then the same performance should be measured during off-season. In this way it can be ascertain how the employee perform according to the scenarios.  

It is essential for a firm to have both long term goals and short term objectives.

The top management needs to set SMART long term goals to set a guideline path for the long term growth of the organisation. These goals must be 

Specific, Measurable, Achievable, Relevant and Time bound.

The individual departmental and regional managers and team leaders need to break these down into SMART short term objectives, aligned to the long term goals, which are easier for the lower level team members to correlate with their respective job functions.