It happens fast. As soon as you set-up a new campaign, Google assigns a quality score to each of your keywords.
A snap judgement before any data is collected.
What exactly are they looking at during this early stage?
Does this mean that if you include your keywords on both your text ads and landing pages that it will produce a high Quality Score off the bat?
The answer is NO.
One of the main consideration that Google takes into account is the historical clickthrough rate of that keyword across all accounts (not just yours).
It's clearly stated as the first formula to determine the quality score of your keyword on their Adwords support page. They use the keywords' historical CTR information to determine how valuable each particular keyword is to their users (the searcher). As a result, sometimes you'll see that certain keywords will start with a low quality score, even if it hasn't run in the account before.
For example, in the case of the keyword "loft", it has a very low quality score in general, most likely because Google assigned that one-word general keywords usually don't entice users to click on ads, and thus resulting in low clickthroughrates and quality scores off the bat.
This means it's important to identify keywords that are valuable to you and what measure you will take to work that keyword, its adtexts, its landing page and ultimately - the desired action you want users to take to produce a conversion.
When you see an assigned quality score right off the bat, take it as a gauge for determining how others are doing with those keywords and if they are having success with it. Low quality score tells me that others have tried and failed.
Is it worth it for your business model to tackle a low historical clickthrough rate for your most targeted keyword?
Are you ready to monitor your stats & adjust your text ads and landing page strategy daily to satisfy the other points of the Quality Score formula that Google clearly spells out (see below link) to dominate and position that keyword to advance your business's exposure?
Only you will know the answer to these questions. However, if you are not ready to do what is necessary based on a low QS indicator from historical clickthrough rate, then you may want to consider either expanding your keyword word-count (ex: expand "loft" to "lofts for sale" or "lofts for rent") or eliminating the keyword altogether.
Do not compromise your business goals and online business objective based on just low Quality Scores.
Google Adwords provides a system where you can succeed with your main keywords based on your business objectives. The platform also provides an indicator to show the advertiser which keywords simply failed or was not worth it to other advertisers.
Adwords Support link on "How is my keyword's Quality Score used":