A Tale of Two (or more) TCOs (3 of 4)
So based on your feedback, existing pilot data, existing TCO research and numbers, and limitations and suggestions from the TCO calculator tools themselves, this is what we’re measuring.
Reduction
The challenge with TCOs is finding the simplest, yet comprehensive, set of boxes and categories to arrange the numbers. The OLPC Workbook separates out costs by country-level costs, school-level costs, per-laptop costs, and program costs, and gives some explanation and examples. The GeSCI TCO takes a much more Ministerial view, combining program costs with country-level costs, and then school set-up costs versus ongoing budget costs, aiming at being a tool to help plan and budget for a 1:1 computing rollout without being specific on the technology being implemented. VitalWave focuses primarily on showing the cost differences among 1:1 projects versus computer-lab centric projects using various hardware styles (netbooks, laptops, used computers, new computers) and the various infrastructure costs each takes.
You can read about the various merits of each of the TCOs and their individual choices for simplification; My goal here is to settle on a set of fair and representative numbers that can be used to compare the various TCO tools out there. Towards that, the first pass will be extremely reductionistic and focus tightly on the per-laptop costs; dividing program and country costs, as well as student and school-level costs over the number of laptops. By using common numbers across all the TCO tools, hopefully this abstract approach will not be too out of whack while also shedding light on where the numbers are least aligned.
Again with the numbers
Project Timeline: 5 years - the magic number from many project estimates and existing budgets.
Maintenance and Repair: Combining replacement with timelines, there are some hiccups with projected computer lifespan, so we’ll be amortizing replacement costs. We’ll go with the popular “1%” repair costs.
Numbers of laptops and people: To get tou our per-laptop costs, we’ll first have to set some standard numbers for plugging in for teachers, schools, and program and/or country costs. We’ll presume 1:1 laptop to school population (teacher and student), with 1 server per school (or per 820 laptops); with a school size of 800 students. This is to avoid a calculation where we dictate 1 server per 1000 laptops and over-spending on servers because the calculations don’t fall out evenly.
“Let’s start off with a basic calculation across these tools. Five years of use, 100,000 laptops in country with 100 servers across 100 schools, with a total 2000 teachers and 80,000 students. That’s 800 students per school, and one teacher for every 40 students.”