Measuring marketing performance in the service, manufacturing, and merchandising sectors can be done using different metrics depending on the specific goals and objectives of your marketing campaign. Here are some common metrics that can be used:

• Return on Investment (ROI): This measures the amount of revenue generated from your marketing efforts compared to the cost of the campaign.
• Customer Acquisition Cost (CAC): This measures the cost of acquiring a new customer, including all the expenses associated with marketing and sales.
• Customer Lifetime Value (CLV): This measures the total value of a customer to your business over their entire relationship with your company.
• Conversion Rate: This measures the percentage of website visitors who take a desired action, such as filling out a form or making a purchase.
• Brand Awareness: This measures the level of recognition and familiarity that consumers have with your brand.
• Customer Satisfaction: This measures the level of satisfaction that customers have with your products or services, which can be determined through customer surveys or other feedback mechanisms.
• Market Share: This measures the percentage of sales within your industry that your company captures.

To effectively measure marketing performance, it's important to define your goals and objectives at the outset, and then choose the metrics that are most relevant to those goals. You may also want to consider using marketing automation software, such as HubSpot or Marketo, to help you track and analyze your marketing campaigns.

You have to first define metrics for what is political instability. Then you have to define parameters for measurement of marketing performance. Now days only financial and quantitative criteria are not used, but both financial and nonfinancial criteria . How political instability affects marketing performance of a firm is not so clear. But yes its effect on country's brand and international business of that country does get affected including foreign investment .Your research title looks odd unless you do better literature survey and come up with cogent reasons to link political instability to micro level performance and macro level performance of country as a whole . Even political instability may not affect all sectors but a few sectors . Unless effect of political instability is defined in terms of various macro and micro economic & social parameters, marketing performance cannot be suitably linked. Such political environment affects investments more than consumer products Hence effect on financial institutions and capital goods industry and infrastructure will be more pronounced. I suggest first do study then identify parameters of instability and then better choose one most affected sector w.r.t to particular country or geography . You can not generalize it globally.

There are many marketing analytics tools available that can help you measure your marketing performance. Some popular options include Google Analytics, HubSpot, Marketo, and Salesforce.