How do you differentiate the procurement of goods, services and works in terms of preparing bidding documents and evaluation of bids?

In case of goods, the specifications of goods, manufacturing process, raw material specifications and past experience of the manufacturer are important. On the other hand, for procurement of services, the qualification/experience of the persons and Terms of reference of the assignment carries more important.

With goods procurement, you shall need specifications, for services you shall needTerms of References (TORs) while you need BOQs for works when preparing bidding documents. 

Bid evaluation for goods isnt as comlicated unless they are high capital purchases, total compliance selection methodology can be used among other methods.

Service bid evaluation could be carried out in two stages with the technical proposal being evaluated first after which a technical evaluation is done for proposals that meet the pre-stated percentage score. A quality -cost based evaluation can also be adopted among other methods.

Works bid evaluations tend to be a bit more complex, given that one has to review the scope of works, work schedule, completeness of BOQs to avoid arithmentic errors, resource and capacity compliance, cash flow requirements etc...

Very useful question indeed. The rules and requirements for preparing bidding documents and evaluation of bids for each of the three categories are different. The terms and conditions, bids evaluation criteria as well as processing procedures for these categories require different treatment. Broadly speaking, in case of goods, the specifications of goods, manufacturing process, raw material specifications and sales track record of the manufacturer are important. On the other hand, for procurement of services, the qualification/experience of the persons and Terms of reference of the assignment carries more important. In case of works, it is the mixture of the two.

Goods:Specifications of goods,raw materials,manufacturing process,terms and conditions and optional criterias.

Work / Services:Technical part

For all three you need to prepare scope of work [SOW] which will be split into two, technical criteria [essential & general criteria] and commercial specifications. Evaluation criterias may vary from organization to organization and situation.

However, basic and essential bidding requirements shall be:

Goods: Specifications of goods, specification of raw materials, manufacturing process, lead time, sales track record, terms and conditions and optional criterias

Work / Services: technical part of SOW contains; essential technical criteria,general criteria, quality assurance, HSE record, terms & conditions, service record,financial status etc.

Inprocurement; specifications, Terms of References (TORs) and BOQs for works when preparing bidding documents.  Bid evaluation for goods isnt as comlicated unless they are high capital purchases, total compliance selection methodology can be used among other methods. 

need to consider the manufacture slaes record, quality of the product, raw materials and specifiaction of goods, etc. 

With all due of respect to the question, the answer would need long and lengthy answer. But to simplify the answer,we can say that procurment of Goods normally handled thru issuing ap PO, BPO,or Supply Agreement due to  complexity or criticality of materilal.

However,Services or Works- if on site in perticular - are handled thru Service Agreement/Contract.

Both should have Terms & Conditions suitable to the nature of the goods,services or work required.

There are some differences in the in the documentation and Evaluation between the Good on one side and the Services & Work on the other hand  pertaining to the manpower involvement.Such dufferences are:

- Bidding Invitation & Acceptance Document

- Clear & defined Scope of work documents

- Design and drawings documents

- Insurance coverage certifcates

- Financial Statements in some cases

- Manpower CV review 

- Pre-bid Meetings documentation

- Sealed Bid Offers in some of the companies

- Bids Opening / Evaluation Commitee 

- Work Schedule and Milestones for the jobs

- For Goods, MSDS and materila Specs. are required

These are some of the differnces and not all  in breif.