The part of the sentence "the objective of this study is" is correct and can be used in written English. For example, you could use this sentence to start a research paper, like: "The objective of this study is to investigate the extent to which social media affects young people's mental health and well-being.".
The objective of this study is twofold.
Therefore, the objective of this study is threefold.
The objective of this study is to provide information to inform the selection of delineation method.
The objective of this study is to optimize CO2 separation technologies for Chinese refineries.
The objective of this study is to provide a design process of PCCP rehabilitation.
The objective of this study is to understand and analyze these processes in different contexts.
The objective of this study is to evaluate the compliance of antibiotics prescribed in emergencies.
Being a terminologist, I care about word choice. Ludwig simply helps me pick the best words for any translation. Five stars!
Maria Pia Montoro
Terminologist and Q/A Analyst @ Translation Centre for the Bodies of the European Union