Mistakes are a great educator when one is honest enough to admit them and willing to learn from them.
– Alexander Solzhenitsyn
Even after 30+ years of evaluation, I make mistakes 
. It may be a mistake that occurs in the planning and modeling; it may be a mistake that occurs in the implementation, monitoring, and delivery; or a mistake in data management (qualitative or quantitative); or more than likely, a mistake in the use of the findings. 
Probably the biggest mistake 
I have ever made was making an assumption 
at the planning stage.
Assumptions 
are a form of bias that is pervasive in humon; we cannot escape the bias with which we grow up, the bias that come from the various systems we experience daily, the bias we read, see, and hear from the media. Some of those biases are so subtle that we do not know that we are being exposed to them, they just become a part of us as we go about our work, our lives. This is important to recognize. We assume that what worked will always work. We do not take into consideration the changes that have occurred–changes to systems, changes to locale, changes in you. We tend to think that what we see is all of what there is, like the ice berg 
when we know that the majority of the ice berg is below the water. I’ve been studying bias since the early 1980s. (I did my dissertation on personal and situational bias.) I work hard to NOT make assumptions. I fail miserably.
I make assumptions without even knowing it. I wonder how much is a function of my privilege and how much is learned and did I learn it because of my privilege? I do not know. Are my assumptions always a reflection of that learning (and privilege)? Probably.
What was that mistake I made that has stuck with me? One that was based on assumptions I did not clarify? In the planning stage? I assumed that the docs who had agreed to “play” were in charge. They were not. This assumption put me (and the grant from NIDA) way behind. I learned (then at least) to clarify my assumptions. I still work on clarifying my assumptions.
my 
.
molly.
I believe that,
Mistakes are mistakes until you learn from them and build/do something better avoiding those mistakes.
after that Those mistakes become Lessons.
Pari, Although the target audience for my blog is people interested in or involved in evaluation, I value the comments that come from other individuals. It is apparent that my agenda for creating a safe place for conversation is working with you (based on your comments). Thank you. Many of the posts are written and I don’t know what effect they have.