This is the freedom you have in finding the people, equipment, sites and assets you need to perform your project. Some projects are provided unrestricted access to resources, some are tightly bound. All of the other characteristics can be negatively affected if this characteristic is tightened, or improved if this is allowed to float.
A low number means that you have good access to resources needed, a high number means that your execution will be heavily affected by access to resources.
Practical Example: a low number leads the Project Manager to plan the job using task linking without gaps. No need to consider resource availability. Everything you need is available. A high Resource Constraint number will result in a plan driven by resource availability, probably with noticeable gaps appearing between tasks, as you wait for something or someone to be freed up for your use.
The freedom you are allowed will be limited by many things. Your organization may not be set up to use contractors or cross charge people or assets in different divisions, for example. There may be certifications or special technical knowledge necessary to do the job, like a CAD tool or specially trained operators. There may be only specific capital intensive setups where certain aspects of the job can be performed, like a very expensive test range. If a new big job is landed, do you hire for it or wait for the right people to become available? Is there a financial penalty for using subcontractors (check how they are loaded by your organization, it varies). Do you have a capital investment in a process or division that must be recouped?
More Engineers have trouble understanding this parameter than the others. Probably because in an engineering culture, this is not generally considered. Operations, on the other hand, gets this immediately. They only have so many of these, the line is only so long, etc. Changes in resource availability are a frightening consideration in most planning cultures. But it is an important consideration on any project and organization.
Lets examine two extremes:
I am staffing up for two web development jobs. They have radically different Resource Constraints.
1) In one case, I need to develop a lot of similar websites, I have a style guide and a test crew. There are as many web developers as I would like to get. Most importantly, our company does not object to using subcontractors, and we have a good system for testing their work and paying them (or not paying them if the work is not sat). In this case Resource Constraints are very low, and I can divide and plan the job to optimize other characteristics.
2) In another case, I need to develop a website with high corporate visibility, with unstable requirements that are being fought over. Everyone likes the work of one developer, who reports directly to the VP of IT. He has done a few prototypes, but does not have a style guide. He does a good job, but does not delegate well. In this case, the resource constraints are very high. It would be difficult to bring additional resources to bear on this. Schedule, NRE, Recurring, Process, Specification will all take a back seat to Resource Constraints, and Performance (due to the corporate visibility).
This is a black and white example, but it shows the extremes. In case 1), your company has invested in an infrastructure to allow resource freedom (quality structure, test, subcontracting), and you are probably expected to take advantage of it. In case 2), trying to staff up and break out work to others would be very painful. Look elsewhere for improvements.
You have a job where Process is at 10, and Resource Constraints are a 1. Process is not typically emphasized at your company, but you could not pass up this job. Beefing up the staff to do the job has been blessed.
In this case, you probably should hire a consultant that exactly versed in the process you must adhere to. This is especially appropriate if you are working for a major contractor like Bechtel or Lockheed. You can probably find a Quality consultant who even knows his counterpart, and really smooth things out. Problem solved. This will help the schedule, and will probably hurt the Non Recurring Budget. How about Technical Performance? A good guy will make this very high, important, if the customer values it.
What if Both Process and Resource Constraints are high?
On the other hand, If Process is a 10, and Resource Constraints are a 9, then your Quality guy, stretched across all your projects, will just have to try to keep up. This will hurt your schedule, and may affect the Specification and but your Non Recurring budget will better.
How do I Take Advantage of Low Resource Constraints?
If Specification is high, and Resource Constraints are low, you can use a dedicated requirements management engineer. This person will build a requirements matrix, determine verification methods, maybe even organize and perform the testing. Since she should be good at it, it should be cheaper than doing it yourself, other than the brief in costs. If Resource Constraints are high, you are doing it yourself. Theoretically, this is cheaper, if you can do it.
Historically, I have been able to perform as a Project Engineer with 10% of the engineering hours (includes monthly reviews). System engineering comes in at about 12% to 20%, depending on the difficulty of the customer or stakeholders. Running through a few numbers, you can handle both jobs if your manloading works out to 4-5 equivalent engineers, and a good customer - a relatively small job. You may be able to squeeze it in with a difficult customer, but you will be challenged, in that the work for the planning and the requirements management are at about the same time.
So if the job is bigger than just a few people, or Schedule is critical, you will need a dedicated requirements person. Theoretically, it will not affect your Non Recurring Cost. This person may may go to sleep or just work part time during design, or they may perform some other roll on the job, and you can save the brief in costs.
While having Resource Constraints very low can help you with Specification, Schedule, Recurring Cost, and Process, it typically does not help much with Technical Performance. That is because Technical Performance usually depends on the skill of the particular individuals doing the work. These people have a better idea of the trade between Technical Performance and the other aspects of design, and are usually your crack designers, and as such expensive and unavailable. So if you need compliance, get lots of people. If you need performance, you will probably be resource constrained.
What if Your Resource Constraints are High?
High Resource Constraints can affect your Non Recurring Costs, in that you cannot get the right person for the job. By definition, if you are using someone at the wrong level of skill or background for the assignment, you will get a penalty in Schedule, Non Recurring Costs, or both. When you have isolated Resource Constraints as an issue, you have identified something that your management can help out with.
Other examples of Constrained Resources:
Spending at a specific rate. For complex financial reasons, some programs must spend at an exact rate. This obviously affects your planning. Unfortunately, I don't think that MS Project will level for internal cash flow. Maybe the next version.
Special Test Facilities - security requirements, unique capabilities.
System Integration Lab. If the system is large, and expensive, there won't be many assets available to do testing. The cost of Non Recurring would be too high.
Work requires unique security clearances
Unique technical skill sets
Sacred Cows - you must use or avoid a facility or personnel group
Approved Vendors
Overhead function - Overhead functions are manpower limited, and you may depend on performance from them. These may be configuration management, finance, shipping, construction, etc. I once made the mistake of accepting that test equipment on a program would be done as an overhead cost. Unfortunately, this expenditure was visible at the highest level. As a result, I ended up structuring the whole job so that the test equipment (10% of the effort) would meet its budget! It wasn't intentional, it just worked out that way.
Local Content Requirements, 8A requirements, Technology/License Restrictions, Contractual Workshare requirements.