Need Help with DAX Measure Using LINESTX and Dynamic Filtering

[Anonymous]

Hi everyone,

I'm working on a DAX measure that performs a linear regression on cost data and then predicts the cost for the end of the current month. I'm using the LINESTX function to calculate the slope and intercept of the regression line. Below is the code I'm working with:

LinestX = 
VAR azcost_agg = 
    SUMMARIZECOLUMNS(
        azcost_f[DT_DATE],
        azcost_f[ID_SUBSCRIPTION],
        FILTER(
            azcost_f,
            azcost_f[DT_DATE] >= DATE(YEAR(TODAY()), 1, 1)
        ),
        "TotalCost", SUM(azcost_f[N_CostInBillingCurrency])
    )

-- Apply the LINESTX function and extract coefficients
VAR cost_prediction = 
    ADDCOLUMNS(
        LINESTX(azcost_agg, [TotalCost], [DT_DATE]),
        "Slope", SELECTCOLUMNS(LINESTX(azcost_agg, [TotalCost], [DT_DATE]), "Slope1", [Slope1]),
        "Intercept", SELECTCOLUMNS(LINESTX(azcost_agg, [TotalCost], [DT_DATE]), "Intercept", [Intercept])
    )

-- Extract specific values
VAR slope = MAXX(cost_prediction, [Slope1])
VAR intercept = MAXX(cost_prediction, [Intercept])

-- Calculate the prediction for the end of the current month
VAR prediction = slope * EOMONTH(TODAY(), 0) + intercept

RETURN 
    prediction

My questions:

1. Is this measure written correctly? Specifically, I'm concerned about how I'm handling the LINESTX function and extracting the slope and intercept. Are there any improvements I should make?
2. How can I make this measure dynamic based on user-selected filters? I want the regression to recalculate automatically when a user applies different filters in the report. Right now, I'm worried that the SUMMARIZECOLUMNS might not be respecting the user's selections. Is there a way to make this more dynamic?

Any insights or suggestions would be greatly appreciated! Thanks in advance for your help.

[bhanu_gautam]

@Anonymous , To ensure that the measure respects user-selected filters, you should use ALLSELECTED or REMOVEFILTERS to control the context in which the regression is calculated. This will allow the measure to dynamically recalculate based on the filters applied in the report.

LinestX =
VAR azcost_agg =
SUMMARIZECOLUMNS(
azcost_f[DT_DATE],
azcost_f[ID_SUBSCRIPTION],
"TotalCost", SUM(azcost_f[N_CostInBillingCurrency])
)

-- Apply the LINESTX function and extract coefficients
VAR cost_prediction =
LINESTX(azcost_agg, [TotalCost], [DT_DATE])

-- Extract specific values
VAR slope = MAXX(cost_prediction, [Slope])
VAR intercept = MAXX(cost_prediction, [Intercept])

-- Calculate the prediction for the end of the current month
VAR prediction = slope * EOMONTH(TODAY(), 0) + intercept

RETURN
prediction