Количественные характеристики всегда полезны - мы можем измерять результат. Привожу основные формулы из курса PMBoK пятого издания.
Project Time Management
Three-Point Estimating - оценка по трем величинам
Применяется для определения продолжительности задачи с учетом рисков.
The accuracy of single-point activity duration estimates may be improved by considering estimation uncertainty
and risk. This concept originated with the program evaluation and review technique (PERT). PERT uses three
estimates to define an approximate range for an activity’s duration:
The equation for the TCPI based on the BAC: (BAC – EV) / (BAC – AC).
If the cumulative CPI falls below the baseline (as shown in Figure 7-13), all future work of the project will need to be performed immediately in the range of the TCPI (BAC) (as reflected in the top line of Figure 7-13) to stay within the authorized BAC. Whether this level of performance is achievable is a judgment call based on a number of considerations, including risk, schedule, and technical performance. This level of performance is displayed as the TCPI (EAC) line.
The equation for the TCPI based on the EAC: (BAC – EV) / (EAC – AC).
Performance Reviews
Variance analysis. Variance analysis, as used in EVM, is the explanation (cause, impact, and corrective actions) for cost (CV = EV – AC), schedule (SV = EV – PV), and variance at completion (VAC = BAC – EAC) variances.
Trend analysis. Trend analysis examines project performance over time to determine if performance is improving or deteriorating.
Earned value performance. Earned value performance compares the performance measurement
baseline to actual schedule and cost performance.
Project Time Management
Three-Point Estimating - оценка по трем величинам
Применяется для определения продолжительности задачи с учетом рисков.
The accuracy of single-point activity duration estimates may be improved by considering estimation uncertainty
and risk. This concept originated with the program evaluation and review technique (PERT). PERT uses three
estimates to define an approximate range for an activity’s duration:
- Most likely (tM). This estimate is based on the duration of the activity, given the resources likely to be assigned, their productivity, realistic expectations of availability for the activity, dependencies on other participants, and interruptions.
- Optimistic (tO). The activity duration based on analysis of the best-case scenario for the activity.
- Pessimistic (tP). The activity duration based on analysis of the worst-case scenario for the activity.
- Triangular Distribution. tE = (tO + tM + tP) / 3
- Beta Distribution (from the traditional PERT technique). tE = (tO + 4tM + tP) / 6
Project Cost Management
Earned Value Management - метод освоенного объема
Earned value management (EVM) is a methodology that combines scope, schedule, and resource
measurements to assess project performance and progress.
EVM develops and monitors three key dimensions for each work package and control account:
Planned value. Planned value (PV) is the authorized budget assigned to scheduled work. It is the
authorized budget planned for the work to be accomplished for an activity or work breakdown structure component, not including management reserve. This budget is allocated by phase over the life of the project, but at a given moment, planned value defines the physical work that should have been accomplished. The total of the PV is sometimes referred to as the performance measurement baseline (PMB). The total planned value for the project is also known as budget at completion (BAC).
Earned value. Earned value (EV) is a measure of work performed expressed in terms of the budget
authorized for that work. It is the budget associated with the authorized work that has been completed. The EV being measured needs to be related to the PMB, and the EV measured cannot be greater than the authorized PV budget for a component. The EV is often used to calculate the percent complete of a project. Progress measurement criteria should be established for each WBS component to measure work in progress. Project managers monitor EV, both incrementally to determine current status and cumulatively to determine the long-term performance trends.
Actual cost. Actual cost (AC) is the realized cost incurred for the work performed on an activity during a specific time period. It is the total cost incurred in accomplishing the work that the EV measured. The AC needs to correspond in definition to what was budgeted in the PV and measured in the EV (e.g., direct hours only, direct costs only, or all costs including indirect costs). The AC will have no upper limit; whatever is spent to achieve the EV will be measured.
Schedule variance. Schedule variance (SV) is a measure of schedule performance expressed as the
difference between the earned value and the planned value.
Equation: SV = EV – PV
Сost variance. Cost variance (CV) is the amount of budget deficit or surplus at a given point in time,
expressed as the difference between earned value and the actual cost.
Equation: CV= EV − AC.
Schedule performance index. The schedule performance index (SPI) is a measure of schedule efficiency expressed as the ratio of earned value to planned value.
Equation: SPI = EV/PV
Cost performance index. The cost performance index (CPI) is a measure of the cost efficiency of budgeted resources, expressed as a ratio of earned value to actual cost.
Equation: CPI = EV/AC
Forecasting
As the project progresses, the project team may develop a forecast for the estimate at completion (EAC) that may differ from the budget at completion (BAC) based on the project performance.
EACs are typically based on the actual costs incurred for work completed, plus an estimate to complete (ETC) the remaining work.
The project manager’s bottom-up EAC method builds upon the actual costs and experience incurred for the work completed, and requires a new estimate to complete the remaining project work.
Equation: EAC = AC + Bottom-up ETC.
EAC forecast for ETC work performed at the budgeted rate. This EAC method accepts the actual
project performance to date (whether favorable or unfavorable) as represented by the actual costs, and
predicts that all future ETC work will be accomplished at the budgeted rate. When actual performance is unfavorable, the assumption that future performance will improve should be accepted only when supported by project risk analysis.
Equation: EAC = AC + (BAC – EV)
EAC forecast for ETC work performed at the present CPI. This method assumes what the project has experienced to date can be expected to continue in the future. The ETC work is assumed to be performed at the same cumulative cost performance index (CPI) as that incurred by the project to date.
Equation: EAC = BAC / CPI
EAC forecast for ETC work considering both SPI and CPI factors. In this forecast, the ETC work will be performed at an efficiency rate that considers both the cost and schedule performance indices. This method is most useful when the project schedule is a factor impacting the ETC effort. Variations of this method weight the CPI and SPI at different values (e.g., 80/20, 50/50, or some other ratio) according to the project manager’s judgment.
Equation: EAC = AC + [(BAC – EV) / (CPI × SPI)]
To-Complete Performance Index (TCPI)
The to-complete performance index (TCPI) is a measure of the cost performance that is required to be achieved with the remaining resources in order to meet a specified management goal, expressed as the ratio of the cost to finish the outstanding work to the remaining budget. TCPI is the calculated cost performance index that is achieved on the remaining work to meet a specified management goal, such as the BAC or the EAC.
difference between the earned value and the planned value.
Equation: SV = EV – PV
Сost variance. Cost variance (CV) is the amount of budget deficit or surplus at a given point in time,
expressed as the difference between earned value and the actual cost.
Equation: CV= EV − AC.
Schedule performance index. The schedule performance index (SPI) is a measure of schedule efficiency expressed as the ratio of earned value to planned value.
Equation: SPI = EV/PV
Cost performance index. The cost performance index (CPI) is a measure of the cost efficiency of budgeted resources, expressed as a ratio of earned value to actual cost.
Equation: CPI = EV/AC
As the project progresses, the project team may develop a forecast for the estimate at completion (EAC) that may differ from the budget at completion (BAC) based on the project performance.
EACs are typically based on the actual costs incurred for work completed, plus an estimate to complete (ETC) the remaining work.
The project manager’s bottom-up EAC method builds upon the actual costs and experience incurred for the work completed, and requires a new estimate to complete the remaining project work.
Equation: EAC = AC + Bottom-up ETC.
EAC forecast for ETC work performed at the budgeted rate. This EAC method accepts the actual
project performance to date (whether favorable or unfavorable) as represented by the actual costs, and
predicts that all future ETC work will be accomplished at the budgeted rate. When actual performance is unfavorable, the assumption that future performance will improve should be accepted only when supported by project risk analysis.
Equation: EAC = AC + (BAC – EV)
EAC forecast for ETC work performed at the present CPI. This method assumes what the project has experienced to date can be expected to continue in the future. The ETC work is assumed to be performed at the same cumulative cost performance index (CPI) as that incurred by the project to date.
Equation: EAC = BAC / CPI
EAC forecast for ETC work considering both SPI and CPI factors. In this forecast, the ETC work will be performed at an efficiency rate that considers both the cost and schedule performance indices. This method is most useful when the project schedule is a factor impacting the ETC effort. Variations of this method weight the CPI and SPI at different values (e.g., 80/20, 50/50, or some other ratio) according to the project manager’s judgment.
Equation: EAC = AC + [(BAC – EV) / (CPI × SPI)]
To-Complete Performance Index (TCPI)
The to-complete performance index (TCPI) is a measure of the cost performance that is required to be achieved with the remaining resources in order to meet a specified management goal, expressed as the ratio of the cost to finish the outstanding work to the remaining budget. TCPI is the calculated cost performance index that is achieved on the remaining work to meet a specified management goal, such as the BAC or the EAC.
The equation for the TCPI based on the BAC: (BAC – EV) / (BAC – AC).
If the cumulative CPI falls below the baseline (as shown in Figure 7-13), all future work of the project will need to be performed immediately in the range of the TCPI (BAC) (as reflected in the top line of Figure 7-13) to stay within the authorized BAC. Whether this level of performance is achievable is a judgment call based on a number of considerations, including risk, schedule, and technical performance. This level of performance is displayed as the TCPI (EAC) line.
The equation for the TCPI based on the EAC: (BAC – EV) / (EAC – AC).
Performance Reviews
Variance analysis. Variance analysis, as used in EVM, is the explanation (cause, impact, and corrective actions) for cost (CV = EV – AC), schedule (SV = EV – PV), and variance at completion (VAC = BAC – EAC) variances.
Trend analysis. Trend analysis examines project performance over time to determine if performance is improving or deteriorating.
Earned value performance. Earned value performance compares the performance measurement
baseline to actual schedule and cost performance.
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