---
# System prepended metadata

title: Reading Lighthouse Performance Metric Scores

---

# Reading Lighthouse Performance Metric Scores

All tests of Lighthouse are run in a controlled setting.
A home computer is **not** running in this kind of environment.
Lighthouse is **very** sensitive to location conditions that can
be present on home computers. For instance:

* **Connection speed**

    A home computer may not have access to a connection as fast as that used by
    JnJ for its tests.  

* **Network traffic**  

    A home computer shares its Internet connection with everyone else in your house.
    If you have a cable modem, you are sharing bandwidth with everyone in your immediate
    neighbourhood. All of this  results in lower speeds. Lighthouse will perform
    more slowly in such conditions.  

* **Device Power**  

    A home computer may not be as powerful as the ones used by JnJ to test Lighthouse.  

* **Other CPU Activity**  

    Lighthouse runs best when running alone. Running other programs with Lighthouse can
    make Lighthouse run slowly. Running other tabs in a browser may also make Lighthouse
    run slowly.

* **Antivirus Software**

    Antivirus software, in particular, can slow the performance of Lighthouse on your PC.
    **This does not mean that you should not run antivirus software.** It may, however, 
    explain why Lighthouse does not perform as quickly on your computer as it does in the
    test environment.

* **Browser Extensions**

    Some browser extensions are known to reduce performance in a browser.
    This can also make Lighthouse run slowly.

* **Geographic Distance to Server**

    Your computer may be farther away from the server hosting Lighthouse than JnJ's test
    network.

Thank you for your understanding as JnJ continues its work on the Lighthouse project.
