During the initial phases of any project, there are multiple technical solutions that the team could choose from for the overall design or for individual technical details. These various options need cost comparisons for effective selection and decision making. It sometimes is a challenge for the team, to get everybody involved to agree on a single solution. But a proper layout and presentation of these estimates could help to ease the understanding and in the decision making.
When presenting an option selection cost estimate, it is very important to tabulate the varying scopes (at a high level), alongside the costs to transparently present the differences in scopes between the various options. I would also recommend presenting all the options in a single tabulation if possible. This helps in easy comparison of the scope differences and then to see how the overall cost varies. A single tabulation would help during any discussions with the technical team and might highlight any items that could have been missed or not defined correctly when compared to each other.
Also, the unit cost basis for any individual item should not vary between the options. Any variation in unit cost should imply a new item description. The only difference between the options should be the quantity of individual items. Keeping the same unit cost basis gives the confidence to the decision makers that they really are choosing between different technical options. Do note that there could be specific items in an option that may not be required for other options.
Attached is a dummy template that could be used for any option selection estimate. I have personally used similar tabulation for various study estimates and successfully helped in the decision-making process.
Design Option Selection Estimate template (free estimating resource)
Case in point:
In a particular project, involving a wide range of technical solutions, various options were estimated and the cost summaries of the individual options presented separately. This did not easily allow the decision makers to understand the technical differences between the options. When reviewing the cost estimate, most of the time was spent in understanding the technical differences and the reasoning behind them, as it was not easily obvious why the costs of the various options were so different, and what benefit did the project get by investing more money. The technical scope and costs being separated, did not lend itself to easy decision making and no decision was taken. It took the team months to select an option.
I have been practicing presenting design option estimates in a single page layout and have most of the times successfully convinced the team to easily understand the various options technically and commercially. This has always been helpful in decision making and sometimes only within a single meeting.
Note:
Not all items that are included in an option selection estimates can necessarily become part of a single project. For instance, when deciding between two plot spaces for a process plant, the road that needs to be built could be of different length in each option and might help decide which is a more favourable overall cost project, but the actual road might not be included in the project scope at all.
This example shows that all scope differences, even beyond the current project boundaries, should be considered when trying to select between various competing designs and projects.