How is the Performance score calculated?

We provide a comprehensive evaluation of over 11,000 dealership websites across the, analyzing their performance based on speed, responsiveness, and stability.

This document details our methodology for calculating the performance scores, the metrics involved, and their respective importance.

Metrics Definition and Weighting

Our scoring system utilizes five key metrics derived from web performance best practices. Each metric is assigned a weight based on its impact on user experience.

First Contentful Paint (FCP)

Measures the time from page load to the first content rendered. Lower FCP improves perceived load speed.

RANGE:

1000ms - 6000ms

WEIGHT:

15%

Largest Contentful Paint (LCP)

Indicates the load time for the main content. Key for retaining user attention.

RANGE:

1000ms - 8000ms

WEIGHT:

25%

Cumulative Layout Shift (CLS)

Measures visual stability; lower CLS means fewer unexpected layout shifts.

RANGE:

0 - 0.8

WEIGHT:

30%

Time to First Byte (TTFB)

Assesses the server response time. Faster TTFB means a quicker start to loading.

RANGE:

250ms - 3000ms

WEIGHT:

15%

Interaction to Next Paint (INP)

Evaluates the responsiveness to user interactions. Crucial for a smooth user experience.

RANGE:

100ms - 1000ms

WEIGHT:

15%

Scoring Calculation

Each metric contributes to the total score based on its actual measurement against our established 'best' and 'worst' values. The contribution of each metric is calculated as follows:

Metric Score = (1 - ((Value - Best) / (Worst - Best))) × Weight

Where:

Value: The actual measured value of the metric.
Best: The "ideal" value for the metric.
Worst: The "poorest" acceptable value for the metric.
Weight: The relative importance of the metric in the final score.

The total performance score is the sum of the weighted scores for all metrics. For metrics exceeding their "worst" value, their contribution is zero.

Example Calculation

Suppose a website has the following performance metrics:

FCP: 2500ms
LCP: 3500ms
CLS: 0.1
TTFB: 500ms
INP: 200ms

The scores for each metric would be calculated as follows:

FCP:

(1 - ((2500 - 1000) / (6000 - 1000))) × 0.15 = 0.09

LCP:

(1 - ((3500 - 1000) / (8000 - 1000))) × 0.25 = 0.21

CLS:

(1 - ((0.1 - 0) / (0.8 - 0))) × 0.3 = 0.29

TTFB:

(1 - ((500 - 250) / (3000 - 250))) × 0.15 = 0.14

INP:

(1 - ((200 - 100) / (1000 - 100))) × 0.15 = 0.14

Summing up these contributions results in a total performance score of:

Total Score = 0.09 + 0.21 + 0.29 + 0.14 + 0.14 = 0.87 (or 87%)

In this example, the performance score is 87%, reflecting a strong overall website performance.

Conclusion

The performance score provided by DealerDB reflects a holistic view of a website's health, focusing on elements that directly affect user experience. Improving these metrics can lead to better user engagement, satisfaction, and ultimately, higher conversion rates.

For specific improvement strategies and more detailed explanations, dealerships are encouraged to consult resources such as Google's web performance guides.