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Updated February 2026

Nahla AI now supports two ways to bring Actual Cost data into your EVM analysis — automatically from your schedule, or via CSV upload for full control.

7 min read February 27, 2026 EVM · Dashboard

Earned Value Management (EVM) depends on three data points: Planned Value (PV), Earned Value (EV), and Actual Cost (AC). Without accurate Actual Cost, your CPI, SPI, EAC, and other performance metrics are incomplete.

Nahla AI now gives you two ways to source Actual Cost data — so you can get full EVM analysis regardless of how your project tracks costs.

Option 1 — Automatic

Schedule S-Curve Data

Your XER or XML file already contains S-curve data with AC from Primavera P6 resource assignments. No extra upload needed.

Option 2 — Override

CSV Actual Cost Upload

Upload a CSV with monthly actual costs to override the schedule data. Ideal when finance provides separate cost reports.

Automatic from Your Schedule

When you upload an XER file (from Primavera P6) or an XML schedule that includes resource assignments and cost loading, Nahla automatically extracts the S-curve data containing time-phased Planned Value, Earned Value, and Actual Cost.

This means your EVM metrics — CPI, SPI, EAC, VAC, TCPI — are calculated immediately after upload with no additional steps required.

How It Works

Primavera P6 stores resource assignments with rates and quantities at the activity level. When you export an XER or XML file, this cost data is embedded in the schedule. Nahla's processing engine reads these resource assignments and builds the cumulative S-curve over the project timeline:

• Planned Value (PV) — The baseline budget spread across time, based on planned resource usage and rates
• Earned Value (EV) — The budgeted cost of work actually performed, calculated from physical percent complete
• Actual Cost (AC) — The actual expenditure recorded against resources up to the data date

Once processed, the Dashboard's Earned Value tab displays the full S-curve chart and all EVM performance indicators. No CSV upload, no manual data entry — it all comes from the schedule.

When does this work best?

Automatic AC extraction works best when your Primavera P6 schedule has accurate resource loading — meaning resources are assigned to activities with proper rates and actual units are recorded during progress updates. If your schedule tracks costs at the resource level, this option gives you instant EVM with zero extra effort.

Upload CSV Actual Costs

Not every schedule has accurate cost loading. Sometimes the planning team tracks schedule progress while the finance team tracks costs in a separate system. For these situations, Nahla lets you upload a CSV file with monthly Actual Cost data that overrides the schedule S-curve AC values.

When you upload a CSV, Nahla replaces the AC line in the S-curve with your CSV data while keeping PV and EV from the original schedule. All EVM metrics recalculate based on the new AC values.

Step-by-Step Guide

• Open the Actual Costs Upload

On the Dashboard, navigate to the Earned Value tab and click the "Upload Actual Costs" button. This opens the CSV upload dialog.

• Download the Pre-Populated Template

Click "Download CSV Template". Nahla generates a template with one row per month, spanning the project's start to finish date. The months are pre-filled; you only need to enter the cost values.

• Fill In Monthly Actual Costs

Open the CSV in Excel or any spreadsheet application. Enter cumulative actual cost values for each month. Leave future months blank or at zero — only fill in months where actual expenditure has been recorded.

• Upload the Completed CSV

Save the file and upload it back through the dialog. Nahla validates the format, maps the dates to the S-curve timeline, and recalculates all EVM metrics instantly.

CSV Format Requirements

The CSV must use the template format provided by Nahla. Each row represents a month with a date and a cumulative actual cost value. Values should be numeric (no currency symbols or commas). The template handles the date formatting automatically — just fill in the cost column.

The EVM Source Toggle

Once you have both data sources available — the schedule S-curve data and a CSV upload — Nahla lets you switch between them instantly using the EVM Source Toggle on the Dashboard.

Where to Find It

The toggle is located on the Dashboard's Earned Value tab, near the top of the EVM section. It shows two options:

Schedule S-Curve

CSV Actual Costs

What Happens When You Toggle

Switching the EVM source triggers an instant recalculation across the entire dashboard:

• S-Curve Chart — The Actual Cost line updates to reflect the selected data source. PV and EV curves remain unchanged.
• EVM Metrics — CPI, SPI, EAC, VAC, and TCPI all recalculate based on the new AC values at the data date.
• Info Ribbons — The summary cards at the top of the Earned Value tab update to show the recalculated values.
• Cost Breakdown — Any cost tables or breakdowns adjust to reflect the selected AC source.

The toggle state persists for your session, so you can navigate between tabs and return to the Earned Value tab without losing your selection.

No Data Loss

Toggling between sources does not delete or modify either data set. Both the schedule S-curve AC and your uploaded CSV AC are preserved. You can switch back and forth as many times as needed to compare the impact on your EVM metrics.

When to Use Which Source

Choosing the right AC source depends on how your project tracks costs and where the most reliable cost data lives. Here is a quick guide:

Consideration	Schedule S-Curve	CSV Actual Costs
Setup effort	None — automatic	Download template, enter data, upload
Data source	P6 resource assignments and rates	Finance system / cost reports
Best when	Schedule has accurate cost loading	Finance provides separate AC data
Accuracy	Depends on resource loading quality	As accurate as your finance data
Update frequency	Updates with each new XER upload	Updates when you upload a new CSV
Typical users	Planners / schedulers	Project controls / cost engineers

Consideration

Schedule S-Curve

CSV Actual Costs

Setup effort

None — automatic

Download template, enter data, upload

Data source

P6 resource assignments and rates

Finance system / cost reports

Best when

Schedule has accurate cost loading

Finance provides separate AC data

Accuracy

Depends on resource loading quality

As accurate as your finance data

Update frequency

Updates with each new XER upload

Updates when you upload a new CSV

Typical users

Planners / schedulers

Project controls / cost engineers

Use Schedule S-Curve When:

• Your P6 schedule has detailed resource assignments with accurate rates and actual units
• The planning team updates actual costs during progress updates in P6
• You want instant EVM without any additional data entry or file preparation
• The schedule is your single source of truth for both time and cost

Use CSV Override When:

• Your finance or cost control team provides monthly actual cost reports separately from the schedule
• The schedule does not have reliable cost loading (e.g., resources without rates, or lump-sum activities)
• You need to reconcile EVM metrics against independently verified financial data
• Different stakeholders track costs in different systems and you want to use the finance-approved numbers

Understanding the Impact

The choice of AC source can significantly affect your EVM metrics. Since CPI is calculated as EV / AC and EAC as AC + (BAC - EV) / CPI, even small differences in Actual Cost values ripple through every performance indicator.

For example, if your schedule overstates actual costs (perhaps because resource rates in P6 are higher than what the contractor actually charges), the schedule-based CPI will appear worse than reality. Switching to CSV actuals from the finance system would correct this and give you a more accurate picture of cost performance.

Conversely, if the schedule has detailed cost tracking but the finance system only provides high-level monthly totals, the schedule S-curve may give you better time-phased granularity for your EVM analysis.

Key Metrics Affected

Metric	Formula	Impact of AC Source
CPI	EV / AC	Higher AC lowers CPI (indicates over budget)
SPI	EV / PV	Not directly affected (uses PV, not AC)
CV	EV - AC	Higher AC increases cost variance (negative = over budget)
EAC	AC + (BAC - EV) / CPI	AC affects both directly and through CPI
VAC	BAC - EAC	Cascading effect from EAC change
TCPI	(BAC - EV) / (BAC - AC)	Higher AC reduces remaining budget, increasing required efficiency

Metric

Formula

Impact of AC Source

CPI

EV / AC

Higher AC lowers CPI (indicates over budget)

SPI

EV / PV

Not directly affected (uses PV, not AC)

CV

EV - AC

Higher AC increases cost variance (negative = over budget)

EAC

AC + (BAC - EV) / CPI

AC affects both directly and through CPI

VAC

BAC - EAC

Cascading effect from EAC change

TCPI

(BAC - EV) / (BAC - AC)

Higher AC reduces remaining budget, increasing required efficiency

Pro Tip

Use the toggle to quickly compare metrics between the two sources. If they produce similar CPI and EAC values, you have high confidence in your cost data. If they diverge significantly, investigate the source of the discrepancy — it often reveals cost tracking issues that need attention.

Summary

Nahla AI supports two paths to Actual Cost data for Earned Value Management. Schedule S-curve data gives you automatic EVM from your XER or XML file with zero extra effort. CSV upload gives you full control when finance provides separate cost data. The EVM Source Toggle on the Dashboard lets you switch between sources instantly, with all metrics recalculating in real time. Use whichever source best represents your project's true cost position — or compare both to validate your data.

Try It on Your Next Project

Upload your XER file and see EVM metrics calculated automatically. Add a CSV when you need full cost control.

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