How can we be sure that the Mary Harvey, transported aboard the Sea Queen to Van Diemans Land (now known as Tasmania in Australia) is also the Mary Edwards of Devon in England as well as the Mary Pearson of Hobart in Tasmania?
The answer is by using genealogical proof standards, it is reasonable to rely on the results.
The Genealogical Proof Standard  has five basic elements:
- – reasonably exhaustive research
- – complete and accurate citations
- – analysis and correlation of all sources
- – resolution of conflict among evidence items
- – soundly reasoned and coherently written conclusions
Golden rule 1:
Begin with what is known and work backwards. 
This is how it transpired
Using information gleaned from her Conduct Record  it has been possible to piece together some of Mary’s early life.
Her native place is recorded in her convict record as Clodden, Devonshire. Allowing for spelling and pronunciation variations, and taking advantage of the text prediction algorithm in the Google search engine, it was possible to speculate Clawton as being the town. She is listed as being married to William, a sailor, and her mother is listed as Jane EDWARDS. It is reasonable to assume that she was most likely born Mary EDWARDS.
It is likely that she was baptised on 4 September 1814 in Clawton , Devon England.  In spite of her seemingly common name, this is the only record of a Mary EDWARDS baptised between 1813 and 1817 in Clawton with a mother named Jane.
A William HARVEY married a Mary EDWARDS on 27 July, 1836 in Stoke Damerell, Devon, England, the only record of a William Harvey to marry a Mary Edwards in Devon between 1830 and 1840. 
Five years later, in the 1841 England Census in Stoke Damerell, there is a thirty-year-old Mary HARVEY and a thirty-year-old William HARVEY,  with two children but there is no mention of Mary having children at the time of her transportation. There is another thirty-year-old Mary HARVEY with five other women.  However, a twenty-five-year-old Mary HARVEY with a fifty-five-year-old Jane EDWARDS  appear in a house with numerous other people (possibly a lodging house). No William HARVEY is listed with either of the previous two records, however his trade was given as Sailor and so it is reasonable to assume that he could have been at sea. The Census entry with Jane Edwards gives the street address as Mill Street (link is external), this is the address given by Mary as her mother’s and so it is reasonable to assert that this is the convict Mary Harvey. It also links Mary Edwards of Clawton to Mary Edwards then Mary Harvey of Stoke Damerell.
In conclusion, it is likely that Mary HARVEY was born Mary EDWARDS and baptised on 4 September 1814 in Clawton, Devon England. On 27 July, 1836 she married William Harvey, a sailor, in Stoke Damerell, Devon, England. On 6 June, 1841 Mary HARVEY and her mother Jane EDWARDS were listed in the England Census in a house on Mill Street in Stoke Damerell, Devon.