• Please Remember: Members are only permitted to share their own experiences. Members are not qualified to give medical advice. Additionally, everyone manages their health differently. Please be respectful of other people's opinions about their own diabetes management.
  • We seem to be having technical difficulties with new user accounts. If you are trying to register please check your Spam or Junk folder for your confirmation email. If you still haven't received a confirmation email, please reach out to our support inbox: support.forum@diabetes.org.uk

Standard Deviation?

Status
This thread is now closed. Please contact Anna DUK, Ieva DUK or everydayupsanddowns if you would like it re-opened.
Phil65

Phil65

Well-Known Member
Relationship to Diabetes
Type 1
My meter averages look quite good lately, 6.8 for last 7 days, 6.8 for 14 days, 6.9 for 30 days, 7.0 for 60 days, 7.1 for 90 days.........and my SD is between 3.8 and 3.9.....is that a good SD reading or not?
 
Hi Phil

Is that on the Expert?

Mine is the first meter I've owned that offered an SD. From a quick Google, I now understand that it gives an assessment the 'spread' of results. Somehow it manages to do this in a way that reflects 'most' not 'all' I think, so that it's not exactly a max-min measure, more of a 'mostly' spread.

Handily SD is expressed in the same units as the measurements themselves and (again I think I've got this right) shows + and - the mean/average.

So if your SD is 4 and your average is 10 then most of your readings are between 6 and 14. (ie 10-4 and 10+4).

Obviously the lower the SD the less 'wobbly' your results have been. My better periods of control seem to have SDs below 3, though I don't know if there is any kind of recommended target for them.

Maybe someone who understands a bit better can give a clearer explanation of how it works?

M
 
Last edited:
HelenM said:
According to Hirsch

the standard deviation multiplied by two needs to be less than the mean (or average). Ideally, he says we should multiply by three, but this is difficult for anyone with type 1 diabetes
Click to expand...

but this of course only applies if you have sufficient readings.
Click to expand...

My SD has generally been around 1.7-1.9 based on an average of 6-8 tests a day according to my meter software 🙂 I'd need to multiply by 3 really to get close to my average BG over time.
 
Northerner said:
My meter software gives it but not the meter. I think the meter that gives it is the Accu check Expert.
Click to expand...

Which might also mean the Accu-Chek Combo remote?
 
I can get mine when I upload to the software form my nano. It doesn't give the Hb unfortunately, but that can be deduced.

I tend to think that an SD of about 2.5 or less is good but I would see 3 or more as needing some attention. It's allegedly the high to low swings that do the damage, so the tighter the control, ie. the lower the SD, the better, and if you have an expert or equivalent, you can presumably track any improvements in real time.🙂

Rob
 
Is there a way for people who don't have those meters to work their SD out?

Thank you 🙂
 
You can do it on the windows calculator
(in accessories)
Click the View menu, and then click Scientific.

Type or click your first piece of data, and then click Sta to open the Statistics Box dialog box.

Click RET to return to Calculator, and then click Dat to save the value.

Type or click the rest of the data, clicking Dat after each entry.

Click Ave, Sum, or s.

Notes
Ave calculates the mean of the values saved in the Statistics Box dialog box, Sum calculates the sum of the values, and s calculates the standard deviation
Click to expand...
 
Phew! The wiki link made me a bit 😱

Thank you 🙂
 
Thanks for your responses, I think I will just concentrate on my averages! My readings have been very good lately and my averages are in the 6s with 7-8 tests a day, I have never had a SD of less than 3.6....so the maths doesn't really work out for me.
 
According to this article, you should aim for an SD of no more than a third of your mean (average) BG.

So, if your average is 6, your ideal max SD should be 2. That's hard to acheive but will improve your overall risk of complications and, maybe, your HbA1c too.

It's something else to aim for at least and it benefits no-one but ourselves.

Rob
 
Phil65 said:
Thanks for your responses, I think I will just concentrate on my averages! My readings have been very good lately and my averages are in the 6s with 7-8 tests a day, I have never had a SD of less than 3.6....so the maths doesn't really work out for me.
Click to expand...

I 'm not sure this is quite how SD works, - very roughly from what I remember 95% of the results fall within +/- SD from the average, 99% results fall within 2xSD +/- average and 100% results within 3xSD +/- average. So the lower the SD the better, and the more results the more accurate and representative the SD is.
eg with an average of 7.0 and an SD of 3.6, 95% of the results would have been 3.4-10.6.
 
and XL does calculate SD, using the same data used to measure the average. My HbA1c is good, reflecting the avarage BG, but my SD is too high, reflecting too many high and low BGs, so it is still quite a useful measure. I think getting a good average is a good start to go from!
 
Status
This thread is now closed. Please contact Anna DUK, Ieva DUK or everydayupsanddowns if you would like it re-opened.
Back
Top