Nowadays the speed of Internet is much better than in the past, but we can still see websites with high loading time.
Low-performing websites move away users and produce several negative side effects, for example:
- low reputation of the website;
- bad advertisement for the service, firm or business the website represents.
For this reasons we are going to analyse the performance and usability of a website.
We have chosen, as small representative sample for the study, the homepage of most well-known Italian newspapers because we think they are accessed every day from lots of users so their performance should be very crucial.
These homepages have been studied using GMetrix : a website performance analytics tool that provides professional reports.
Taking a significant subset of data produced by GMetrix we have the following table:
In the analysis, the parameter pivot is the Fully Loaded Time.
Measuring some statistical relationship between the parameters in the table above by using the Pearson’s correlation coefficient we have the results shown in the following table.
The use of Pearson correlation coefficient (PCC) reveal: a small correlation between Fully Loaded Time and Total Page Size, a moderate correlation between Fully Loaded Time and Total Image Size and a Strong correlation between Fully Loaded Time and Total of HTTP Requests.
Some considerations is necessary on the Total Number of HTTP requests.
We have two type of request:
HTTP requests that respect the Same Origin Policy (SOP)  which means they belong to the same domain identified by protocol:hostname/anything:port, generally fast.
HTTP requests that are out of the domain and gather information from other websites, generally slow:. This type of requests have a negative impact on the performance especially when we have a lot of requests.
We can affirm that the Fully Loaded Time of a web page could be considered good when its value is <= 5sec. This generally happens when:
R01. Total Image Size < 50% of Total Page Size with a tolerance of 15%;
R02. Total Number of the requests that do not respect the SOP are at maximum 30-40%;
R03. Total Number of the request is maximum around 200.
These simple statements could be considered suggestions and general guidelines with a good validation in practice.
 Tai Wen Jun, Low Zi Xiang, Nor Azman Ismail. William Goy Ren Yi, Usability Evaluation of Social Media Website, International Research Journal of Modernization in Engineering Technology and Science, January 2021;
 https://gtmetrix.com, GMetrix ;
 https://en.wikipedia.org/wiki/Pearson_correlation_coefficient Pearson correlation coefficient;
 https://en.wikipedia.org/wiki/Same-origin_policy Same-origin policy;