No description available.

No description available.

No description available.

No description available.

When building large buildings, such as compartment buildings, there is a number of deliveries arriving on the construction site daily. In order to receive these deliveries without disturbing the rest of the work going on JM often books a fixed unloading time. When doing that they can be prepared when the delivery arrives. Making sure there is a suitable unloading area, someone to meet the delivery and when needed proper machines, such as a tractor or a crane, to help unload bigger deliveries. The person receiving the delivery is supposed to make an acceptance control where they check the delivered goods making sure nothing has been damaged in transport and that they have received what they were supposed to receive. Also noting whether the delivery arrived on time or not.   In 2010 JM introduced structured production as their take on lean, and thus working more effectively. Structured production at JM means that everyone in the company performs the same task in the same way according to a predetermined assembly instruction. It also includes a certain way to make time plans for the whole project as well as for the next 5 weeks. As for deliveries JM tries to order these as close to just in time as possible. That reduces keeping material in stock at the construction site and also handling this material more than necessary. Handling material in stock is a big source of accidents and takes time away from other work. However, it is very vulnerable to have essential supplies arrive to the construction site just when they are needed as a delay can ruin the whole timeline of the production.   This report aims, through qualitative studies, to find out how widespread the problem of late deliveries is at JM'S three construction sites in Uppsala and what JM is able to do to avoid it.   The study showed that if deliveries are delayed, it refers almost exclusively to 1-5h on the desired delivery date. Deliveries being delayed so that they do not arrive on the right day were very unusual. One of the questions in the interviews was also whether JM themselves could have a negative effect on deliveries arriving on time by making changes in their orders, but this seems to have no significance when changes are made only after approval by the supplier and that the vast majority of deliveries after all still arrives on the right day. It rather seems that some providers take the order of a fixed unloading time less seriously. Something that does not make things better is that the procedure for handling delayed deliveries varies a lot just between the three construction sites in Uppsala and also between supervisors on the same construction site. It is not even always the case that the supplier is notified that the delivery was late, and then they do not know that they need to improve. Most suppliers buy in the transport of a shipping company and order a fixed unloading time from them. The suppliers interviewed all said that they wanted to know if the delivery was late so that they can contact the shipping company.

Whilst considerable research has found that people tend to underestimate their task completion times (e.g., Buehler et al., 1994), factors that might influence the accuracy of temporal predictions have received little empirical treatment. The research presented in this thesis identified two distinct factors that mediated time estimation accuracy and bias. One factor was task duration, whereas the other factor was the person’s prior experience of the task. There was evidence that having prior experience of performing all or a substantial part of the same task enabled participants to more accurately estimate its duration. Additionally, predictions were more accurate when participants viewed tasks before making time estimates. Contrary to the theory of the planning fallacy (Kahneman & Tversky, 1979), these findings suggest that people do take account of their previous task performance, and use such distributional information to good effect. However, there was evidence of time prediction bias when unrelated tasks were completed beforehand, suggesting that erroneous information about previous task performance was used when making a subsequent estimate. The directional nature of time estimation bias was also highlighted in the present research. In general, there was some evidence of temporal overestimation on tasks with a duration of up to four or five minutes, whereas participants tended to underestimate their completion times on tasks that took between eight and 16 minutes to complete. These findings indicate that task duration influences the direction in which time estimates are biased (i.e., under or overestimation), with the temporal underestimation indicative of the planning fallacy occurring on tasks of at least eight minutes' duration. The present research has potential implications for task duration estimation in everyday life, and outlines conditions under which prediction bias can be reduced. The present findings are discussed in relation to the theory of the planning fallacy and the potential role of cognitive judgemental heuristics in determining temporal misestimation.

No description available.

No description available.

No description available.

No description available.