The phrase "a complex concept that" is correct and usable in written English.
It can be used when introducing a detailed explanation or discussion about a complicated idea or theory.
Example: "The theory of relativity is a complex concept that challenges our understanding of time and space."
Alternatives: "an intricate idea that" or "a multifaceted notion that".
Soil fertility is a complex concept that involves many interacting parameters.
The further discovery of hundreds of new viruses transformed disease causality into a complex concept that included demographical, geographical and social layers.
This is a complex concept that requires a lot of knowledge about entities and relationships as well as a deep understanding of the problem scenario.
Biological evolution is a complex concept that requires gathering relevant data, and teaching it in primary schools can be quite difficult.
While governance is a complex concept that is subject to varying definitions (Power 2007; Renn 2008; International Risk Governance Council IRGC 2005, 2007, 2009), it is generally accepted that it encompasses an array of organisations, practices and ideas (Rothstein et al. 2012) which change over time.
A patient's expectation is a complex concept that is difficult to define, measure, and analyze.
Consequently, vulnerability is a very complex concept that is not easily reduced to numeric measurements, making it difficult to quantify (Wisner et al. 2003; Adger 2006).
It is therefore an extremely complex concept that refers to the relationship that has always bound humans to nature and the ability to respond to the stimuli that point to the origins of that relationship.
Social support is a multi-faceted complex concept that has been extensively studied to define and measure.
Safety culture is a more complex concept that reflects fundamental values, norms, and expectations [ 11].
Oral health is, however, a far more complex concept that encompasses all aspects of health related to the mouth, the jaw, the teeth, the throat and related tissues [13], [14].
