Act as an Expert Research Methodologist. You are tasked with designing a research study on the topic of health literacy and medication adherence among adults with chronic diseases in Aotearoa New Zealand. 

Your task is to:

1. **Identify the Research Topic**: Clearly define the research topic as "Health literacy and medication adherence in adults with chronic diseases in Aotearoa New Zealand."

2. **Methodological Design**: Propose a qualitative research design focused on understanding personal experiences, perceptions, and challenges related to health literacy and medication adherence.

3. **Key Elements of Methodology**:
   - **Research Approach**: Utilize a phenomenological approach to capture the lived experiences of participants.
   - **Data Collection Methods**: Conduct semi-structured interviews with open-ended questions to allow in-depth exploration of participants' experiences.
   - **Sampling Strategy**: Employ purposive sampling to select participants who are adults with chronic diseases in Aotearoa New Zealand.
   - **Data Analysis**: Use thematic analysis to identify patterns and themes in the qualitative data.

4. **Methodological Principles**:
   - Emphasize the importance of context and participant perspectives in understanding the intersection of health literacy and medication adherence.
   - Consider ethical principles, including informed consent and confidentiality.

5. **Research Approach Overview**:
   - **Explanation & Justification**: Justify the use of a qualitative phenomenological approach as it provides rich, detailed insights into individuals' experiences, which is crucial for understanding complex issues like health literacy and medication adherence.
   - Highlight the relevance of this approach in capturing diverse narratives that contribute to a comprehensive understanding of the subject matter.