Definition by Wiki
A Quantity Surveyor (QS) is a construction industry professional with expert knowledge on construction costs and contracts. They are not to be confused with Land Surveyors or Land Survey Engineers.
Indeed, I would say a professional quantity surveyor is a combination of an accountant and a lawyer in the construction industry, they should have good understanding on construction cost and contract clauses., as well as construction technolgy. If you want to know whether someone is a professional quantity surveyor, you can simply ask him how much is the cost of a building, a mall, etc.
工料測量，在國內稱為造價工程師，在我看來他們像是工程界的律師和會計師的結合。工料測量師必須對建築成本瞭如指掌，同時對各種建造合約有深入了解，亦要具備建築技術的理解，才可稱為一名合格的工料測量師。如果你的朋友是一名工料測量師，你大可以隨便問問他，建一座大廈到底要用多少錢喔，作為工料測量師他是應該心裡有數可以回答你這個問題的。
The public always question that why does the mega-size project costs that much, indeed construction cost can always be divided into three aspects. I am not going to analysis how to accurately estimate on building cost as it might be too dull to all of you!lol. But the following principle should inspire you as it is the basis, it can also be applied on fitting out works which might be more related to you.
市民經常會質疑為何建造價格會這樣昂貴，聽起來過百億去建一條大橋頓覺得是天文數字，更會質疑會否是官商勾結造成。其實簡易的建築成本計算大體分為三個方向，我不會在這裡深入探討如何盡確地計算建造成本，因為我怕悶壞了你們哈哈。但以下簡單的基礎原則其實在建築任何一方面也能用到，日常生活的裝修維修等等也可以利用以下的方向去簡易推算成本的。
Basically, you can always estimate a construction works by dividing the cost into labour, plant and material, as well as overheads and mark-up. Thereby, a quantity surveyor should be familiar with the material cost like concrete, rebar, sand, etc, different kind of skilled labour cost and plant cost like excavator, crane lorry, compactor, roller, etc.
其實計算建築成本簡單來說可分為人工，物料，機械及利潤。因此，工料測量師/造價工程師必須熟悉各種物料價錢(如石矢，鐵料，河沙等等), 各種技術工人價錢 (雜工，釘板工，紮鐵工等等)和機械價錢 (天秤，挖泥機等等)。
This is only the basic principle in estimating construction cost, of course it may vary by many different factors, for instance, minimum charge, unexpected obstacles (like encountering underground utilities resulting high construction cost, this always happen in majority of the civil engineering projects), etc. Furthermore, the construction cost might keep going up and down, as the material cost, labour cost varies all the time due to many reasons, for instance, government policy, demand & supply.
Feel free to ask if you have any questions regarding quantity surveying. Next, if you find it interesting, I might also briefly discuss different tendering system for your information :)
I hope you enjoy my sharing :)
以上只是建造價格的基礎，它會被很多不同的因素影響，如過小型的建築會被最低價格影響，或是大型基建最常遇到不能預測的障礙(如地下線)而導致高昂的建築費用。 另外，建築成本是會不斷變化的，因為各類的開支就如上述之人工，物料及機械價錢是浮動的，他們會被政府的政策影響 (如出入口限制)，需求和供應量等等。
歡迎留言如你對工料測量/造價工程有任何的疑問。如有人有興趣，下一次可以跟大家探討一下最常聽到的工程招標，不同類型的招標方法，建築成本又有什麼區別呢?
希望你們會喜歡我的分享。