In a recent post, I said that 30 was the rule of thumb, i.e., 30 cases was the minimum needed in a group to be able to run inferential statistics and get meaningful results.  How do I know, a colleague asked? (Specifically,  “Would you say more about how it takes approximately 30 cases to get meaningful results, or a good place to find out more about that?”) When I was in graduate school, a classmate (who was into theoretical mathematics) showed me the mathematical formula for this rule of thumb. Of course I don’t remember the formula, only the result. So I went looking for the explanation. I found this site. Although my classmate did go into the details of the chi-square distribution and the formula computations, this article doesn’t do that. It even provides an Excel Demo for calculating sample size and verifying this rule of thumb. I am so relieved that there is another source besides my memory.


New Topic:

I will be attending the 15th annual Engagement Scholarship Consortium ESCLogo  meeting this fall. I’ve submitted a poster, titled Is blogging just outreach? Can blogs also engage? My contention is that reading is a form of engagement and analytics will support that. I am gathering support from my readers and their comments. Two comments are posted below.

“Blogging provides two distinct benefits, engages the reader with new content, but also expands on the sites cyber footprint, thus increasing CTR and Impressions in the search engines.”

“I would say blogs that have regular readers and are engaged with commenting are definitely making a difference.”

These are different takes on engagement from what passes for engagement, where it is assumed that the “target audience” is engaged when the target audience is contributing. An evaluation colleague calls this “doing as”. Extension has always been about the process of “doing to”; lately (in the last 15  years or so), Extension has moved into the arena of “doing with” .  When Extension  consistently  implements a program “doing as”, outreach and engagement will be the norm. What do you think, reader–are blogs a form of engagement?

My two cents.





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4 thoughts on “30 is the rule of thumb…

  1. There would seem to be a continuum of engagement that happens when blogging. Blogs can generate a somewhat weaker form of engagement — for example, when the reader pauses to reflect on a topic based on questions posed in the blog. Or – they can generate stronger engagement when a reader comments on a post or shares that blog post with others. I would suggest that either would be legitimate ‘engagement’.

  2. Perhaps engagement can happen by SEO exposure? Perhaps by individual reflection and comment posting? I would love to know what you are doing to determine if your blog is making a difference.

  3. Thought provoking question Molly. So…a couple of thoughts.
    1. The first quote you offer – that there are two distinct benefits – I find a bit troublesome (and am hoping that it is one statement within a broader discussion). The benefits offered there are very power-centric on the part of the blogger. It positions the blogger as the knowledge expert and the reader as a rather passive recipient. I prefer to think of blogging as a conversation starter, whether online or off. Good comments expand upon and elevate a post, adding to the knowledge base and thoughts offered within the post. On some blogs, the comments are far better than the blog itself, and I appreciate the blogger for helping to start the exchange.
    2. Extrapolating on item 1, we need not think of blogging as occurring in a silo and thus the engagement as happening only on the blog. I’ve met – IRL (in real life) – a range of people because I blog. They’ve read something that I wrote and that writing offers us a common spot from which to network, collaborate, learn, and build friendships.
    3. Taking this tangent one step farther, I live in a relatively rural area with few professional colleagues nearby. Blogging and participating in the exchanges around blogging (commenting, emails from colleagues about something posted, etc.) provide an avenue through which I can maintain and strengthen my personal and professional network.

    As a concrete example. I read your blog and comment occasionally not only as a way to learn, but also as a way to continue our distant, but valuable, friendship. Thank you for sharing and for caring.

  4. Susan,
    The first quote about two distinct benefits is complete in and of itself. I offered it as a readers response for engagement even though the reader was responding to a different post. I, too, see blogging as a conversation starter–we agree there. I’m not sure that I agree with the reader quoted…I’m thinking about that because I WILL be presenting the poster in October. I rarely get comments that have substance (i.e, conversation starters) so when I get one which has substance, I keep it. Hence, the quoted material. Whether or not readers share the information outside of their circle (of a silo) I can’t know. I can only read the analytics, even though there are people who tell me they read my blog when I meet them or I know people who blog (you) with whom I connect. I had an interesting conversation with an Extension IT person today about community, doing to, with, and as. I agree that there are communities which focus on the content (either generally or specifically); I don’t know (to use Chris Lysy’s example) whether I have evidence that they are engaged. This week’s blog asks for folks to comment in more depth. They haven’t, yet; they have visited the blog. So am I engaging them? I don’t know…I think in the world of social media the definition of engagement (engaged scholarship) needs to be redefined–it may no longer be face to face…Thanks for your thoughts. I will worry this for a while–at least until October…:) Enjoy your holiday–eat blueberries!
    go peacefully,

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