Keep the results and mark the route-change point explicitly. Separate exposure and observations before and after reassignment, then assess which periods remain comparable to the control. Do not silently blend the routes or discard inconvenient data. The truck's record can remain useful even when its full-season result no longer supports the original product comparison.
Mark the date and separate exposure before and after the change
Record when the route assignment changed, why it changed and which service records locate the transition. Identify the actual blade and equipment configuration at that time. If the change date is uncertain, show the uncertainty instead of selecting a convenient inspection boundary. Preserve the original route data and the new route data as linked periods within the same blade history, so accumulated service is not lost.
Use the vehicle-data discussion to identify relevant logs and their limits. Record differences in duty, working exposure and required finish that can be supported by the fleet's sources. Do not infer exact blade engagement from a route name or assume two routes of similar length imposed the same work. Keep maintenance, operator or treatment changes near the transition visible as well; the reassignment may not have been the only change affecting the observation.
Keep comparable periods and document the new confounding conditions
Compare the pre-change period with the control only where the evidence supports the same defined question. Do the same for the post-change period, using an appropriate comparison if one exists. Avoid creating a new control retrospectively solely because it makes the candidate look favorable. State how any subset was selected and retain the full record alongside it. A narrower supported comparison is preferable to an apparently complete season total with hidden differences.
Check the timing of condition measurements. If the blade was inspected well before and well after the route change, the observed material loss spans both duties. Do not allocate that loss exactly between routes without evidence. Report the mixed interval as such and use later observations to improve the record. This may limit a route-specific wear conclusion while still allowing reporting of actual service, removal events and costs over the complete period.
Use the evidence with limits rather than silently blending or deleting it
Present a timeline showing the route segments, major configuration events and observation dates. Explain which findings apply to the original trial duty, which describe the new assignment and which cannot be separated. Keep the reassignment reason in the report because operational selection can affect interpretation; a truck moved because of a problem should not be analyzed as if the change were random and unrelated to performance.
For a blade evaluation enquiry, describe the changed duty and the decision still needed. The responsible team can decide whether to extend observation, add an appropriate comparison or close the original question with limited evidence. Continue normal service priorities rather than forcing the truck back onto a route merely to preserve a tidy study. The review is complete when the useful data is retained, the confounded interval is visible and the final recommendation does not attribute every post-change difference to the blade itself.
Further reading. Clear Roads evaluation ↗
