Secondary research involves summarizing, collating, and synthesizing existing research rather than collecting primary data directly. It has advantages of being quick and less expensive than primary research but disadvantages in that the data may not be trustworthy, relevant, or up to date due to time lags. Secondary research uses extensive data collected by others to efficiently target specific issues.

1. Secondary research
Secondary research(also known as desk research) involves the summary,
collation and/or synthesis of existing research rather than primary research,
where data is collected from, for example, research subjects or experiments
Disadvantages;
Can’t always trust the data you’re being given
May not include the information you’re looking for.
Information might be out of date (time lag)
Advantages;
Quick to find.
You spend less time/money using other research than having to collect it
yourself.
Data collected by governments and other institutes is usually very
extensive and covers a large spectrum of issues. An organization can
filter that data and consider only parts which they are targeting.