It makes no difference whether your organization is in the public sector or private sector and no difference whether it’s a service, product, or piece of technology. It goes double if the buy requires a (long-term) contract. And it doesn’t matter if there are government, health-and-safety, or other regulatory requirements (as these can always be worded in functional terms or shifted over to manufacturing or raw material requirements).
The reality, and Stephen Guth of the Vendor Management Office will back me up on this, is that as soon as you create a specification, you (essentially) lock in a (small set of) vendor(s). And just like 80% of the cost is locked in during the design phase of new product development (NPD), 80% of the price is locked in as soon as you limit yourself to a vendor (or two). Just like raw materials, components, and machines have relatively stable prices in a narrow band, your average vendor, with stable overheads, supply, manufacturing, and/or service delivery costs, has a relatively stable price band that its sales representatives will not be allowed to deviate from, often because the vendor cannot afford to because of its overhead cost.
Plus, it’s never about the product or service, but the value received from the product or service. Consider a tablet manufacturer. The end customer doesn’t care about the CPU, they care about the performance it delivers. Most customers don’t care if it’s AMD or Intel, just that the performance is on par with best-in-class. Consider outsourced back office accounting. Does it really matter what packages are used or how many resources are assigned to the team? No. What matters is whether acceptable standards are followed, how fast the monthly reporting is completed, and how much the service costs. And consider technology. When one is buying a new e-Sourcing system, the specific 400 features on the drop down lists don’t matter. What matters is whether or not it supports RFX, e-Auction, “What-If” Decision Optimization, and Contract Management; whether or not the workflows can be tailored and/or integrated to your existing Supply Management Systems; and whether or not it’s the most cost-efficient delivery model for your organization. The minute you use a “vendor-supplied” RFx or think you need 20 specific features is the minute a single vendor locks you in and doubles the price because no one else will have their specific feature list, but yet, for an average organization, ten off-the-shelf packages will be equally as effective for the organization in its quest to achieve Supply Management Value.
So forget the specs and focus on the function. That’s the best way to maximize value (and minimize sales person power).