I am trying to estimate the amount of instructional design hours needed to develop a 3 credit hour college CBT course with an equivalency of 45 contact hours. Realizing that there are many variables that impact on the estimated hours for course development, what is the estimated instructional design time (hours and/or days) needed to develop such a course? We are designing it from scratch which will involve conducting audience analysis, context analysis and task analysis. How much time can be estimated to complete each major phase of ISD: so how much time (hours or days) can be estimated to complete the analysis phase (to include all types above), how much time for the design phase, how much time for the development phase and the evaluation phase formative and summative?
Lastly, are there any easy to use formulas on such time estimates?

As you know from your previous experiences, there are many factors that impact how much time one needs to develop something. What does your experience tell you? I'm a bit confused at the fact that you acknowledge there are many factors, but you still request a formulaic answer.

My experience has been that when determining the amount of time a specific task takes, the estimate is based on personal history - plus I always overestimate by1 -2 % to put in "wiggle room" just in case something comes up that disturbs the process. I think most folks do it that way as well.

I know that for Instructor led training, the development time is usually set at 40 hours development time for every 1 hour in the classroom. I did some research last year on this and found that the 40:1 is still pretty accurate but that development time for some form of Web based training is about 125 hours for one hour of seat time. The research and prep time should be about the same. The increase come in on the development time piece.

Good Luck!

Thank you for your feedback.