PM 360 Week 2 Estimating and Scheduling Methods Example

Seventy-Two Hours of Temperature Mapping Before the First Pallet: Estimating and Scheduling a Food Bank's Eight-Week Move

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University of Phoenix

PM/360: Models, Methods, and Artifacts

Week 2 Assignment

[Instructor Name]

[Date]

Valley Harvest Food Bank, its tasks, estimates and dates are composites written for a model paper.

The Week 1 paper introduced Valley Harvest Food Bank, an invented Fresno, California, nonprofit moving into a new refrigerated building and switching from paper pick lists to scanners. Inés Carrillo, who manages the project, must finish the move inside eight weeks and cannot miss a single delivery to the 210 partner pantries. This paper selects estimating and scheduling methods for the move's tasks, applies them and explains how the team guarded its estimates against optimism.

Choosing Methods for Tasks

The current standard presents estimating and scheduling methods as options to be selected for each situation, noting that the right method depends on the information available, the type of work and the level of uncertainty (Project Management Institute [PMI], 2021). The move contains several kinds of work: repetitive truck moves, a stock transfer tied to cold-chain rules, installation tasks with uncertain durations and software configuration whose content is still being discovered. Each gets a different method.

Analogous Estimate for Dry Goods

Valley Harvest moved part of its dry goods to an overflow warehouse in 2021, shifting 620 pallets in 11 working days with two trucks and a crew of six. The new move involves about 1,900 pallets of dry goods over a similar distance. Scaling by pallet count gives about 34 working days for two trucks, or 17 days with four trucks, which the food bank can rent. Analogous estimating is quick and suits repetitive work, but it assumes the past job was similar. The new building's dock is larger, so the team expects the actual figure to be somewhat lower.

Bottom-Up Estimate for Cold Stock

Refrigerated and frozen stock must move fast to protect the cold chain. The team counted current inventory, about 260 pallets in coolers and 140 in freezers, and estimated each step: loading a refrigerated truck with 22 pallets takes about 40 minutes, the 9-mile trip about 25 minutes and unloading into a cold room about 35 minutes. With two refrigerated trucks in rotation, a truck can complete four or five round trips in a ten-hour day, so the pair can manage nine or ten loads; 400 pallets need 19 loads, or about two days. Building the estimate from the smallest pieces fits work where each step is known and timing matters.

Three-Point Estimate for Racking

Racking installation in the new building depends on a contractor and on inspections, so its duration is uncertain. The team estimated an optimistic 8 working days, a most likely 11 and a pessimistic 18, the last allowing for a failed seismic inspection, which California requires for high racking. The weighted estimate is (8 + 44 + 18) / 6, or about 11.7 days, with a standard deviation of about (18 minus 8) / 6, or 1.7 days. The schedule uses 12 days and holds 3 days of buffer before stock transfer begins.

Relative Estimates for System Configuration

The warehouse management system needs configuration: location codes, pick paths, label formats, partner agency order rules and reports. The vendor's consultant, the warehouse leads and the inventory manager sized 26 configuration items using relative points, comparing each with a reference item, the label format, set at 3 points. The total came to 94 points. Based on the vendor's experience with similar clients, the team expects to complete about 20 points a week, suggesting about five weeks. Jørgensen (2004) reviewed studies of expert estimation of software effort and found that expert judgment was often as accurate as formal models, and that combining estimates from several experts tended to improve accuracy; the group sizing session follows that advice.

An estimate made by one person in a hurry is a guess with a number attached.

Building the Schedule

The schedule links tasks by their dependencies. The longest chain runs through the cold rooms: refrigeration commissioning by the contractor (5 days), followed by temperature mapping, which requires 72 hours of logged readings showing every zone holds temperature, then a food safety review (1 day), then cold stock transfer (2 days), then the first pantry orders filled from the new building. Racking (12 days plus buffer) must also finish before dry goods move, and system configuration must finish before the parallel run. Working these chains forward from the project start shows that cold-room commissioning, mapping and stock transfer, together with racking for the cold rooms, form the critical path, leaving the dry goods move and volunteer training with float.

Leveling the Volunteer Peak

The first schedule placed volunteer scanner training, the dry goods move and the first week of pantry picking in week 5, requiring about 140 volunteer shifts in a week when the food bank usually fills 90. Training had float, so the team moved half of it to weeks 3 and 4 in the old building using a practice scanner kit. The peak dropped to about 100 shifts, within reach with a recruitment push.

Compressing One Path

The board wanted the cold rooms in use before the summer stone-fruit harvest, which would bring large donations from growers. The team fast-tracked by starting racking in the dry storage area while refrigeration commissioning was still under way in the cold rooms, since the two use different crews and areas. The risk is congestion and rework if the contractors interfere with each other, so a daily site coordination call was added. Crashing the temperature mapping was not possible: the 72-hour requirement is fixed.

Guarding Against Optimism

Buehler et al. (1994) showed in a series of studies that people predict their own tasks will finish sooner than they actually do, even when they know similar tasks ran late before. The team used three habits to counter this. Estimates were made by the people who would do the work, then compared with records from the 2021 move. Ranges, not single points, were used for uncertain tasks. And for each estimate, the team asked what went wrong last time and whether it could happen again.

Conclusion

Valley Harvest's move uses each estimating method where it fits: analogy for repetitive truck moves, bottom-up counting for cold stock, three points for uncertain racking and relative points for system configuration. A dependency-based schedule shows that the cold rooms drive the finish, leveling smooths a volunteer peak and fast tracking brings the cold rooms forward while the fixed mapping period stays untouched. Grounding estimates in records and ranges keeps the eight-week plan honest.

References

Buehler, R., Griffin, D., & Ross, M. (1994). Exploring the "planning fallacy": Why people underestimate their task completion times. Journal of Personality and Social Psychology, 67(3), 366-381. https://doi.org/10.1037/0022-3514.67.3.366

Jørgensen, M. (2004). A review of studies on expert estimation of software development effort. Journal of Systems and Software, 70(1-2), 37-60. https://doi.org/10.1016/S0164-1212(02)00156-5

Project Management Institute. (2021). A guide to the project management body of knowledge (PMBOK guide) (7th ed.). Project Management Institute.