Recent years have seen a tremendous increase in the capacities and capabilities of Field-Programmable Gate Arrays (FPGA's). Much of this dramatic improvement has been the result of changes to the FPGAs' internal architectures. New architectural proposals are routinely generated in both academia and industry. For FPGA's to continue to grow, it is important that these new architectural ideas are fairly and accurately evaluated, so that those worthy ideas can be included in future chips. Typically, this evaluation is done using experimentation. However, the use of experimentation is dangerous, since it requires making assumptions regarding the tools and architecture of the device in question. If these assumptions are not accurate, the conclusions from the experiments may not be meaningful. In this paper, we investigate the sensitivity of FPGA architectural conclusions to experimental variations. To make our study concrete, we evaluate the sensitivity of four previously published and well-known FPGA architectural results: lookup-table size, switch block topology, cluster size, and memory size. It is shown that these experiments are significantly affected by the assumptions, tools, and techniques used in the experiments.