Dear

If you can divide the period 1957 to date into some sort of distinct groups, you can capture each period using categorical codes and see how each period is affecting your interest variable growth of GDP.

But, the grouping of years should be based on clear policy difference, or other attribute you believe the grouping make sense.

Agriculture alone may not act as growth engine to raise the GDP if it is mostly populated by marginal farmers. Less income and too many people to share the profit and income. It is a very challenging issue for countries where people are mostly engaged in agriculture. It is however my opinion.

Thanks for all the advice, I am indeed grateful

I think you will be able to argue your case more effectively if you can get data specifically on the contribution of the agriculture sector to GDP as your dependent variable. I am not sure how you intend to measure your "various policies" and how you will address issues of spill over effect of other non-agriculture-related policies that have indirect implications for agriculture. Remember also, that Ghana's agriculture is rain-fed, hence, the need to account for climate variability over the years. It is possible, you can do it but you need to think through the process of achieving your objective(s)

So in your view how best can I frame the topic and the objectives@Emmanuel_Orkoh