Google Page Speed Score vs. Website Loading Time

You might have read yesterday’s article titled “Average Page Load Time of Top Ranking Websites in Google.” It conducts a study on the average page loading times of top ranking URLs in Google. You may also be wondering how you can improve the speed at which your own web pages load. Keep reading; this article will show you how to diagnose your technical issues with Google Page Speed.

Google Page Speed is a Firefox plug-in that can help you discover technical issues affecting the average page load time of your website.

Google Page Speed analysis using a Firefox browser measures how optimized the web page is in terms of loading time and provides a quantitative measurement that is known as a “Page Speed” score. This is a rating on a scale from 1 to 100. If a website scores 100, it means it is “perfectly optimized” for fast website loading.

Does Google Page Speed really help in improving a web page’s loading speed?

A Google Page Speed score does tell you if your website is still far from completely optimized for speed. As with every other tool, this might not be a perfect measurement or a true indicator of a slow- or fast-loading website.

Because of this doubt, you might ask: Does Google Page speed really help in improving a web page’s loading speed? Of course, we cannot directly ask the Google developers about this; instead, the best way to prove this is to study the behavior of this tool with respect to actual website loading time.

What about conducting a correlation study between an actual website’s loading time measurement vs. the Google Page Speed score? Well, if there is a “strong” correlation between the two, then you can say that the Google Page Speed score is indeed a strong indicator of a website’s loading performance. For example, say we are interested in finding out whether a high Google Page Speed score corresponds to a very fast loading time, and a low Google Page Speed score corresponds to slow loading time for a web page.

Now if it is indeed true that there is a strong and direct correlation between the Google Page Speed score and the website loading time in seconds, then the problem items and solutions outlined by the Google Page Speed analysis (for example, see the screen shot below) should indeed be an effective solution to improving a website’s loading time.

{mospagebreak title=Data Analysis: Page Speed Score and Website Loading Time Correlation}

The previous article already contained 36 website loading time measurements. So, we are going to use that data and add a new column, which is “Google Page Speed” score. Below is the updated data, including the Google Page Speed scores:

A rough inspection of the raw data provided above shows that a slow-loading website (high loading time) also has a low Page Speed score. But is this an accurate observation? The best way to provide a more accurate observation is to make a scatter plot between the two factors (Google Page Speed and website loading time). Below is the resulting scatter plot:

The scatter plot reveals a strong correlation between website loading time and Google Page Speed score. The plot shows clearly that whenever the website’s loading time is slow (higher value of website loading time), it corresponds to a lower Google Page Speed score. For example, approximating a website loading speed around 27 seconds in the graph corresponds to a Google Page Speed score of ~63.

A fast-loading website (low website loading time), on the other hand, has a high Google Page Speed score. For example, websites that load completely in less than 10 seconds have a corresponding Google Page Speed of at least 80-85.

So to answer the question "Does Google Page speed really help in improving web page loading speed?" the answer is yes, it can help, because once you start implementing Google Page Speed suggestions/recommendations for improvement, your Google Page Speed score will go up, and that will surely translate to a faster website loading time based on the analysis shown above.

{mospagebreak title=What Google Page Speed score is considered normal?}

A lot of webmasters new to this tool might ask “How high of a Google Page Speed is considered normal?” Or, putting it in another way, “How high should we aim for during the improvement process?” Of course, the higher your Google Page Speed score, the better. But how much “higher” is realistic is still a valid question.

This can be answered by analyzing the raw data we used previously. The following are the resulting statistics:

Average Google Speed score (top ranking websites in Google) = 80.78


Standard deviation of the 36 measurements = 6.91

Based on 36 measurements, the average Google Page Speed score is around 80.78. It would be interesting to compute the “range” of the true population average for the Google Page Speed score, as this provides a more useful estimate. You can estimate it by using this tool and setting the following values in the form:

Desired confidence level: 95%

Enter sample size: 36

Enter observed mean: 80.78

Enter observed standard deviation: 6.91

When all of those values are set, click “Calculate.” The resulting range is: 78.52 to 83.04.

This means that the population (all websites ranking in the first position in Google) averages around 78.52 to 83.04 for their Google Page Speed score.

If you are within this range, then your website’s Google Page Speed score is considered “normal” and average. But remember, what is “normal” does not necessarily translate to being “good,” so you might still consider improving your Google Page Speed score.

Based on the data, a “good” or “above average” Google Page Speed score is higher than 83.04. If the optimized URL has a Google Page Speed score greater than 83.04, it is considered to be above average, or have a high Google Page Speed score.

{mospagebreak title=How can I improve my Google Page Speed score?}

The good thing about the Google Page Speed tool in Firefox is that it automatically highlights the technical issues that the website faces, which could slow down the website loading time.

For example, see the screen shot below:

The top priority issues are shown with a red exclamation mark. The yellow triangle indicates minor issues that can be further improved. The rest indicates no problem.

Below are some recommendations on how you can improve your Google Page Speed score:

1. Start with the top priority issues. The best way to tackle the problem is to understand the problem; this makes the problem “half-solved.” Here are some references to help you better understand Google Page Speed reported issues:

2. Always do baseline measurements before starting the improvement process, so that you can compare your data before and after the technical tweaks. This will allow you to see if your improvement efforts really translate to a reduction in the website’s loading time.

3. It is always good to back up website files prior to improvement, as sometimes these tweaks require alteration of the server (for example, enabling “gzip compression” requires some associated tweaks with the server, like in .htaccess or php.ini).

4. Always prioritize the most important pages of your website in the improvement process. The most important page is the landing page with the highest amount of visitors (the home page, for example). If your site experiences a high bounce rate associated with a slow website loading time, then prioritizing these high traffic landing pages can substantially save a lot of website visitors.

As a personal example, my own website, before making improvements, loaded in about 25 seconds and had a Google Page Speed score of 65. I followed Google Page Speed suggestions, and now it loads in 8.95 seconds and boasts a Google Page speed score of 78.

Not everything is as “fixed” as I’ve suggested. There are technical limitations, such as your web host disabling gzip compression modules in Apache, and you cannot enable them without proper server access. Still, you’re likely to find that your bounce rate drops and website traffic substantially increases after the appropriate tweaks.

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