How do customers choose?
The all-important decision of which consultancy is best for the job is not made lightly. This survey certainly showed that clients' trust must be earned - they put reputation high above any other factors when asked how they decide on their consultancy of choice.
So are specialised capabilities really key to attracting clients? This is one area where strategies seem vary widely, with some consultancies aiming to provide across-the-board services while others target a niche audience. This may be a reflection of clients themselves varying in their needs and expectations.
And when clients do want a specialized service, "quite often it's about individuals," AEA Technology's Future Energy Solutions director Cathy Durston thought.
"Sometimes it's about the specialist capabilities of an organization, but quite often clients have worked with someone else before who they felt had the particular capabilities they need," she told edie.
"There are some real niche specialisms out there. Very often we look to partner with them if they're looking to broaden out or if we're looking to bring in specialist skills then we'll partner.
"Many clients want both the specialized capabilities but are also keen to have us as well so that they can have that broader overview," she said.
And many of the factors influencing customers' choice are interconnected. Recommendation and reputation, for example, go hand in hand.
"It's all about the last job you did for them - but alternatively, they may have had us recommended by someone in which case it is about the last job you did for that client," said Cathy Durston.
"The market is increasingly competitive, and you have to deliver excellence every time," she added.
Price appeared surprisingly low down the list - although considering the small gaps between the various factors this may not be as significant a difference as it first appears to be.
Less surprisingly, the consultants themselves judged price to sway clients' choices less than the clients themselves did.
And customers' opinions are certainly worth listening to. As environmental consultancies jostle for a slice of the existing market and booming development in the sector brings new business, attracting clients and an awareness of what they are looking for will determine who will most benefit from the growth.