# Monitoring of Time and Cost Variances of Schedule Using Simple Earned Value Method Indicators
## 3 Results: Application of T/S and T/C Monitoring
The highest T/S values were recorded in this group of scenarios, which results from cumulative variances related to the production stream of works. Monitoring (T/S) in the schedule made according to the assumptions of the parallel performance method shows a typical increase in the analyzed values, together with the increase of the stimulus value, in subsequent scenarios. The highest positive T/S monitoring values were also obtained for the fifth stage, in which activities with the largest budget were carried out. During the sixth inspection period, the lowest negative variance levels were recorded to the assumed time, illustrating the losses of the previous, fifth stage. Monitoring of time variance of the schedule (T/S) in the sequence execution method subject to the influence of local, gradually increasing disturbances, illustrates the planned course of works until the end of the third month. Then the amplitude of fluctuations in the results reflects the modeled disturbances: twice changing the sign-as in the case of the parallel execution method, although in this case the T/S tool recorded jumps of these values five and ten times higher. It results from the specifics and assumptions of the analyzed implementation structure of projects. In all cases, the assumed methods of implementation accepted within them, four scenarios of gradual increase in variances illustrate rational, systematic increases in value, demonstrating the proper operation of the tested computational procedure of T/S monitoring (Figure 4). In the statement of the second and third stage of registration of works in the schedules planned with the methods of parallel and sequence execution, a clear T/S response to previously modeled variances in the structure of parallel execution of works can be seen. Monitoring of variances from the assumed costs of the project (T/C) in the steady execution method illustrates, unlike the other two methods, values greater than zero at all stages of recording the progress of works. This is due to the global nature of modeled time and cost distortions in this method. Similar to T/S monitoring, the largest value amplitudes were noted in the fifth and the sixth stage of registration, in which works with the highest budgets were executed. Figure 4: Monitoring indicator charts in the assumed financial liquidity due to the occurring time variances from the schedule (T/S) in models with a gradually increasing time variance-in the implementation methods according to (from above): steady, parallel, sequence execution of works. Source: [19]. The monitoring of cost variances (T/C) in the method of parallel execution records a zero value in the first stage of registration, in which no interference occurs. Then, the T/C monitoring values remain at 60-70% until the end of the project-the disturbances do not accumulate. Contrary to the above conclusion, in the next method-the sequence execution, T/C monitoring presents overlapping losses in sequence recording stages (resulting from modeled disturbances), starting from the fourth control stage. It results from the basic assumption of this method, in which the time delays of the analyzed sequence of processes affect the delays of its successors. In the first three stages of registration, T/C monitoring records zero values because no distortions were modeled in them. As in the case of T/S monitoring, the definition of four scenarios of gradual increase in interference gives the systematic monotonicity of the graphs of their functions in the project implementation calendar, in each of the structures analyzed (Figure 5). Figure 5: Monitoring indicator charts in the assumed financial liquidity due to arising variances from planned costs (T/C) in models with a gradually increasing time and cost variance-in the implementation methods according to (from above): steady, parallel, sequence execution of works. Source: [19].