Complex sentence: Unlike Reaganomics, his macro-economic policy emphasised the need to narrow the budget deficit rather than engage in unilateral tax cuts; despite these measures the budget deficit remained on average 3% of GDP during Howe's tenure.
Split into simpler sentences: Unlike Reaganomics, his macro-economic policy emphasised the need to narrow the budget deficit rather than engage in unilateral tax cuts. However despite these measures the budget deficit remained on average 3% of GDP during Howe's tenure.