In the world of marketing and customer service, what is the difference between: 1- Closed-end question. 2- Open-end question?

open end questions can be a question where we need elaborate answer and still there could be open ends for answers as there is no choice like YES or NO which customer has in Closed end ones.

For Example - do you have a budget ? Yes or No

How do you make your purchase :? this is a open end question and above is close end.

If the answer to question is either yes or no or it could be multiple choice then to answer or express within explicit options are closed end questions wherease when the answers are in exploratory in nature or answers not within choices given are called open end questions.

Closed-end questions:

1. Answered by yes or no.
2. Answered by pre-given multiple-choice answers? (do you want it for home or office?)

 Open-end questions:

1. Usually start with: why, how, what, which etc. (What model & how big is your car?)
2. Allow for own interpretation of the question.
3. Allow for own formulation of answer.

Asking questions is a basic way to gather information. But like everything else, there's a skill to it. Asking Open-ended questions is a friendly way to engage people in a conversation. Give it a try, you'll be surprised at how effective open-ended questions can be.

Close-ended questions limit the respondent to the set of alternatives being offered and encourages a short or single-word answer. Closed ended questions are direct questions that ask for specific pieces of information from a client. Closed questions have their greatest value when we need to obtain facts and specific pieces of information. By their nature they limit the client's field of choice and length of response.

Open-ended questions allow the respondent to express an opinion without being

influenced by the researcher. An open-ended question is designed to encourage a full, meaningful answer using the subject's own knowledge and/or feelings.

I woud like to suggest here to refer to a class in COPC or SQC here (as I am a COPC practitioner myself).

COPC - customer operation performance center will ideally help you with the designing of open and close ended questions with their critical and non-critical quality and performance driven metrics. This is used by the best companies like Microsoft, Apple, IBM, Aegis and so on.

If you require a week end training over this for your company, please feel free to call me. Regards.

Here is the most important aspect in Sales and Marketing; all depends on the questions you pose either makes or breaks the deal. If you are a clever sales / marketing person you should think whether you need to pose an Open-ended question to get the customer talking for receiving more info; usually this is good at the begining of the sales cycle; or you have to be very cautious when posing a Close-ended question, preferred when you are almost done with closing of sale or deal

CLOSED END QUESTION: is a type of question that could be asked when you expects the answer in "YES OR NO". Closed end questions usually asked when the sales person has already explored the customer's need and just wanted the assurance. e.g., 

As we both agreed that this "scientific calculator" can reduce your workload by25%, would you like to buy one? 

OPEN END QUESTIONS: is a type of question that could be asked when you are in process of exploring customer's need and needs further explanations to sales process. In such case, the customer usually replies in details or further explains about his needs. e.g., 

What type of calculator do you think can reduce your work load ?

tell me about yourself... Open

how old are you in CS??Close

open end questions can be a question where we need elaborate answer and still there could be open ends for answers as there is no choice like YES or NO which customer has in Closed end ones.

In the process of  feature/benefit selling , probing the customer about his choice or need for a particular product in which you are going to present your company product. you make open probs and close probs  to identify customer choice in given situation, by this you clearily know his brand of choice . by this method you have to compare your product to the customer,s brand choice. dont make the brand choice of your customer as bogus product, just give additional advantages of your product to the customer brand of choice. good luck