Some factors that can affect the project variance are unexpected request changes to the design of the project. Changes like these can push back the timeline for a project and can incur more money spent on revising the project putting a project team over their expected budget. A solution for product design changes is to spend more time in the design phase of the project to make sure that all specs are accounted for. Other examples of factors affecting the schedule variance are team members being absent or being dismissed from a project. With team members being absent it can take longer to complete a project, which will push the project behind schedule and can force the company to hire outside contractors for more money to complete the project on time. This will put the budget over the expected budget. Therefore, it is important to communicate with team members can to make sure that all members will be in attendance during the time frame that they are expected to complete their component of the project. Also, another example is problems that can occur during product testing. If the test if not designed properly than more money and time will be spent of creating more test that will provide you with the desired results. A solution to this is to work closely with the design team to come up with a concrete testing method, and to come up with predictions of the test before they are run. BY analyzing all components of the testing before it commences, your team will be better able to assess whether this is the correct testing to administer.

In addition to the factors mentioned by msc52njit-edu that can negatively impact the SV of a project, from my experience working on medical device projects one of the factors which often had a negative impact on SV was supplier delays. Since we outsource all our manufacturing, we depend quite heavily on our suppliers to develop their own timeline for manufacturing our devices. However, sometimes they make unrealistic assumptions and their lead time ends up being much longer than they estimated originally. There are several ways to reduce the possibility of supplier delays. It is important to set expectations early on so the supplier knows that a delay is unacceptable. Possibly charging a fee for late delivery could also motivate the supplier to provide realistic lead times and to deliver on time. Also, it is very important to maintain clear lines of communication and transparency between you and the supplier as this will reduce the possibility of the timeline slipping.

Today has me considering how much weather can negatively affect schedule. This month we have had 5 snow days. Last fall our site in Miami was closed for a week due to a hurricane. Forces of nature are hard to predict and can definitely negatively affect schedule. The best we can do is try and account for those in planning phase. You might want your workers to have the ability to work remotely. You want multiple people trained to perform certain tasks/duties and you would want approvers to be able to delegate authority.

From my experience and as msc52njit-edu and srg36 have mentioned, missing project members due to other commitments may affect the schedule variance. This is because without one person or two, etc. each action item that the team members are in charge of will get delayed. The next time the action items will get worked on is when the person gets back. This could delay the project further since many times each item is tied to each other.

Some factors affecting the schedule variance are: poor baseline schedule, subcontractor or vendor cannot deliver when needed, more or less effort than planned, insufficient resources, labor disputes or work stoppage, unavaibility of resource and requirement changes. According to me solution should be to determine correct threshold and binary thinking.

As mentioned above most have spoken on factors which have a negative outcome on the SV. However, there are positive factors which lead to a positive SV. One of those factors is to use the DHF (Design History File) . A company should have this in their collection of documents. This helps to eliminate errors which have been made in the past. The errors may not just be scheduling issues but, can help in other areas of the project. Anyway, say a DHF has a gnatt chart from a previous project and it had comments as to what impeded the progression of the project, those insightful comments, can help with the projects SV. Also, this can be considered Risk Management what I am posing here as well. Having a risky strategy if a difficult do arise may be bypassed because there is an alternative or fix to the issue currently taking place.

according to me schedule variance can occur due multiple factor especially those factor which affect the causes your project to lack behind in terms of progress and this factors are:
Poor baseline schedule (does it reflect reality?)
Subcontractor/vendor cannot deliver when needed
More/less effort than planned (be specific)
Insufficient resources (staffing)
Labor disputes/work stoppage,
Resource availability (is it there when I need it?)
Requirement changes
Apart from this on of the major factor affecting is planning if things are properly planned first hand than schedule variance can be positive which means ahead of schedule or at least be on schedule.

In my experience, some factors that affect schedule variance negatively involves accounting for unplanned events. Recently we had to complete competitive testing on implants in comparison to our own implants. We had to complete implant characterization but the motors on one of our testing fixtures started stalling. Turns out, the motors were damaged so we had to order two new motors costing about $200 each, which added an additional $400 to the planned budget and also delayed the schedule of completing the competitive testing. It added an additional 2 weeks to complete the testing, which should have been completed in 2-3 days because we had to wait for the motors to come in.

There a multitude of ways schedule variance can occur within industry. We learned from the lecture that schedule variance is the difference between your earned value and planned value. Generally if you have a negative schedule variance, means you are behind schedule in the sense that what your project is worth today is worth less than what it was meant to be worth at that time. Some factors that could affect this are resources not performing up to par or resources leaving prior to the completion of the project. Additional factors could be testing within the project did not go according to plan that puts the project behind, this could also be a result of poor scheduling from the project managers standpoint since he or she did not prepare the schedule to be robust enough in the event of these mishaps.

I agree with the discussion. I had a situation in one of my project that i a worked with at the beginning of my career. I was in the quality control department, where we test some required number of batches coming out of the production site and release that batches, with the test protocol for each specification in the product specification list. One of the senior member was on family vacation for six months. Due to lack of experience in certain critical testing , my manager will not allow me or my peer colleague to work on those testing. I decided to talk to my manager for cross-training . I talked and she agreed. My manger decided to cross-train every person in the laboratory, so that they can avoid this situation.

I believe having a strong baseline schedule is really important. Scheduling seems to be easy but it is never hundred percent accurate. There will always be unexpected events that can throw a team off schedule. For example, one of my coworkers was having trouble for one of his projects, the quality department was taking to long and signing off documents on time. They had to make contingency plans in the meantime however they could not move forward without the signatures. This is one way your schedule can be disturb. There are somethings we can control.

Scheduled value is the result of estimated value minus planned value (SV = EV - PV).
The result for planned value comes from the budget and deadlines set before the start of the execution phase. This means that the estimated value is that factor that will predict if you are ahead or behind schedule. Estimated value is the percent complete multiplied by the original budgeted cost of the task. The only part of these equations that would be altered during execution is the percent complete. Therefore, I agree with the discussion that factors that would affect schedule are task durations. This can be affected by human error or unforeseen setbacks. Proper planning should handle most issues however, there will be some things out of your control as someone mentioned part of a machine being broken. All you would be able to do is try on work on another aspect of the project as you wait for the part to come in. If moving onto another aspect is dependent on the results that are being stalled then your SV would be affected without there being much of a solution.

As @cdj24 mentioned SV=EV-PV. Where EV is the percent complete* original budgeted cost of task and PV is the vale of the work you are supposed to have on a certain date. I agree as others have mentioned that in order to have a positive SV which means you are ahead of schedule, you need to have have a larger percent complete than planned. The factors that would contribute to the success or downfall of an SV would include as others have mentioned; resources including being understaffed/vacation and other unplanned setbacks that would affect the schedule.
I personally have seen that when we contract out a medical device the company will create their gantt chart and timeline, but in order for them to move forward to next critical task they will need sign off from our PI. If it is a surgeon, surgeons are very busy and for larger robotic devices, it usually requires the surgeon to go to in-person to test the device and this can cause setbacks in the timeline due to the busy schedule of the surgeon. Sometimes the contracted party isn't even located in NY so it can really be difficult to make some critical design decisions unless the surgeon is able to test it in person. In some situations the PI wants to then change an aspect of the deign or had another idea and this could add not only to the Schedule Variance but also the Cost Variance. CV= EV=AC (Actual cost). Unfortunately making these changes means that we go over budget. As a solution, we try and address this early on to work with surgeons admin on the critical design/testing milestones meetings to stay in positive SV and educating the surgeons on the importance of spending time on surgeon/user needs upfront so that we don't get behind schedule or over budget re-designing the device, which can be costly and result in us going over budget. Even with these best practices and intentions, unplanned circumstances happen and can still result in a negative SV and CV. I think good planning and communication among all parties involved is really the key to have a positive SV and CV.

The schedule variance could be affected by many factors such as how accurate the project manager was when first establishing the schedule. It is possible that the project manager overestimates the amount of time different aspects of the project will take; in this case the team will likely be ahead of schedule and the schedule variance will be positive. On the other hand if the project manager underestimates how much time certain parts of the project will take the schedule variance may be negative because the team is behind schedule. Other factors that could affect the schedule variance are the schedules and capabilities of the team members, any requests to change the project, and an unplanned issue arising.