Advanced Field Epi:Manual 1 - Disease Investigation - Revision history

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Catriona at 02:06, 10 May 2015

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Catriona at 02:04, 10 May 2015

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Catriona at 10:58, 9 May 2015

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Catriona at 10:44, 9 May 2015

2015-05-09T10:44:01Z

@@ Baris 274: / Baris 274: @@
 '''Diagrammatic representation of the components of an epidemic curve.'''
 ''1= endemic level, 2=ascending branch of epidemic, 3=peak of epidemic, 4=descending branch of epidemic, 5=secondary peak''.
@@ Baris 1.152: / Baris 1.153: @@
 '''Characteristics, strengths and weaknesses of main study types (adapted from Thrusfield, 1995)'''
 {| class="wikitable"
 |-
@@ Baris 1.181: / Baris 1.183: @@
 | style="border-top:none;border-bottom:1pt solid #000000;border-left:none;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0.049cm;padding-left:0cm;padding-right:0.049cm;"| * May be problems with external validity, particularly to diverse target population   * Can be expensive depending on the intervention and situation   * Requires significant cooperation and rigorous management
 |}
@@ Baris 1.537: / Baris 1.540: @@
 ''' Organisation of data into tabular format in preparation for analyses'''
 [[Image:Organisation of data into tabular format.jpg]]
 A variety of simple checks should be performed to try and detect errors and implausible or inconsistent values. Each column can be sorted and the top and bottom rows inspected to look for values that may be outliers or implausible (cow that weighs 45 kg).

← Revisi sebelumnya		Revisi per 10 Mei 2015 04.25
Baris 1:		Baris 1:
		+	<languages/>
	<translate>		<translate>
	= Disease Investigation = <!--T:1-->		= Disease Investigation = <!--T:1-->

@@ Baris 1.046: / Baris 1.046: @@
 <!--T:245-->
-The characteristics of different study types are described briefly below and the advantages and disadvantages of each type are summarised. For more information on epidemiological study design, readers should consult standard epidemiology texts ([#_ENREF_17 Martin et al., 1987];[#_ENREF_23 Thrusfield, 1995];[#_ENREF_20 Rothman et al., 2008]; [#_ENREF_6 Dohoo et al., 2010]).
+The characteristics of different study types are described briefly below and the advantages and disadvantages of each type are summarised. For more information on epidemiological study design, readers should consult standard epidemiology texts ([#17 Martin et al., 1987];[#23 Thrusfield, 1995];[#20 Rothman et al., 2008]; [#6 Dohoo et al., 2010]).
 <!--T:246-->
@@ Baris 1.146: / Baris 1.146: @@
 <!--T:277-->
-{{example|For example, simulation models of the spread of FMD have been used to help understand the behaviour of the 2001 outbreak in the UK and to predict the potential impact of alternative control strategies ([#_ENREF_19 Morris et al., 2001])}}
+{{example|For example, simulation models of the spread of FMD have been used to help understand the behaviour of the 2001 outbreak in the UK and to predict the potential impact of alternative control strategies ([#19 Morris et al., 2001])}}
 <!--T:278-->
@@ Baris 1.610: / Baris 1.610: @@
 <!--T:438-->
-{{example|In 1994, an incident occurred in Queensland where a previously unidentified virus (since characterised as Hendra virus) was responsible for the death of 14 horses and one human (with a second affected human subsequently recovering), associated with a single racehorse stable ([#_ENREF_1 Baldock et al., 1996]). During the investigation it became rapidly apparent that this was a previously unidentified disease, and that the aetiology was unknown. However, even before the causal virus was identified, it was possible to determine that it was probably infectious in nature; was most likely to be directly transmitted; was not highly contagious (either among horses or humans); and that it probably originated from an, as then, unidentified wildlife reservoir ([#_ENREF_2 Baldock et al., 1995]). Just on one year after the Hendra outbreak, flying foxes (fruit bats) were identified as the presumptive natural host of the virus, with about 14% of flying foxes sampled being seropositive ([#_ENREF_1 Baldock et al., 1996]). The virus was subsequently isolated from uterine fluids of a flying fox ([#_ENREF_12 Halpin et al., 1996]). Flying foxes were known to feed in trees in a spelling paddock associated with the stable and in which the index case was grazing prior to becoming sick. The specific mechanism of transmission among bats and from bats to horses is still not known.
+{{example|In 1994, an incident occurred in Queensland where a previously unidentified virus (since characterised as Hendra virus) was responsible for the death of 14 horses and one human (with a second affected human subsequently recovering), associated with a single racehorse stable ([#1 Baldock et al., 1996]). During the investigation it became rapidly apparent that this was a previously unidentified disease, and that the aetiology was unknown. However, even before the causal virus was identified, it was possible to determine that it was probably infectious in nature; was most likely to be directly transmitted; was not highly contagious (either among horses or humans); and that it probably originated from an, as then, unidentified wildlife reservoir ([#2 Baldock et al., 1995]). Just on one year after the Hendra outbreak, flying foxes (fruit bats) were identified as the presumptive natural host of the virus, with about 14% of flying foxes sampled being seropositive ([#1 Baldock et al., 1996]). The virus was subsequently isolated from uterine fluids of a flying fox ([#12 Halpin et al., 1996]). Flying foxes were known to feed in trees in a spelling paddock associated with the stable and in which the index case was grazing prior to becoming sick. The specific mechanism of transmission among bats and from bats to horses is still not known.
 <!--T:439-->

← Revisi sebelumnya		Revisi per 10 Mei 2015 02.06
Baris 1.538:		Baris 1.538:
	[[Image:Organisation of data into tabular format.jpg]]		[[Image:Organisation of data into tabular format.jpg]]

−	~~<!--T:404-->~~
−	~~{\| style="border-spacing:0;"~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\|  ~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\|  ~~
−
−	~~<!--T:405-->~~
−	\|-
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\|~~
−	~~{\| style="border-spacing:0;"~~
−	~~\| style="background-color:#ffffff;border:none;padding:0cm;"\| variable name~~
−
−	~~<!--T:406-->~~
−	\|}
−
−	~~<!--T:407-->~~
−	~~\| style="background-color:#f2f2f2;border:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>'''FARMID'''</center>~~
−	\| style="background-color:#f2f2f2;border-top:0.5pt solid #00000a;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>'''NUMPONDS'''</center>
−	\| style="background-color:#f2f2f2;border-top:0.5pt solid #00000a;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>'''TYPE'''</center>
−	\| style="background-color:#f2f2f2;border-top:0.5pt solid #00000a;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>'''FEED'''</center>
−	\| style="background-color:#f2f2f2;border-top:0.5pt solid #00000a;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>'''ANN_PROD'''</center>
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\|  ~~
−
−	~~<!--T:408-->~~
−	\|-
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\|  ~~
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:0.5pt solid #00000a;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>001</center>
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>3</center>
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>Fish</center>
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>Commercial</center>
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>400</center>
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\|  ~~
−
−	~~<!--T:409-->~~
−	\|-
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| Record 2~~
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:0.5pt solid #00000a;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>002</center>
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>6</center>
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>Shrimp</center>
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>Commercial</center>
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>6000</center>
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\|~~
−
−	~~<!--T:410-->~~
−	\|-
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\|  ~~
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:0.5pt solid #00000a;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>003</center>
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>2</center>
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>Shrimp</center>
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>Self</center>
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>800</center>
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\|  ~~
−
−	~~<!--T:411-->~~
−	\|-
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\|  ~~
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:0.5pt solid #00000a;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>004</center>
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>1</center>
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>Fish</center>
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>Self</center>
−	\| style="background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #00000a;border-left:none;border-right:0.5pt solid #00000a;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>50</center>
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\|  ~~
−
−	~~<!--T:412-->~~
−	\|-
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\|  ~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\|  ~~
−
−	~~<!--T:413-->~~
−	\|-
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\|  ~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>cell</center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\|  ~~
−
−	~~<!--T:414-->~~
−	\|-
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\|  ~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center>data values</center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\| <center> </center>~~
−	~~\| style="background-color:#ffffff;border:none;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"\|  ~~
−
−	~~<!--T:415-->~~
−	\|}
	A variety of simple checks should be performed to try and detect errors and implausible or inconsistent values. Each column can be sorted and the top and bottom rows inspected to look for values that may be outliers or implausible (cow that weighs 45 kg).		A variety of simple checks should be performed to try and detect errors and implausible or inconsistent values. Each column can be sorted and the top and bottom rows inspected to look for values that may be outliers or implausible (cow that weighs 45 kg).

@@ Baris 1.536: / Baris 1.536: @@
 ''' Organisation of data into tabular format in preparation for analyses'''
-[[Image:Organisation of data into tabular format.jpg|300px|centre]]
+[[Image:Organisation of data into tabular format.jpg]]
 <!--T:404-->

← Revisi sebelumnya		Revisi per 10 Mei 2015 01.58
Baris 1.382:		Baris 1.382:

	<!--T:363-->		<!--T:363-->
−	[[Image:Sample size calculation matrix.~~svg~~]]	+	[[Image:Sample size calculation matrix.jpg]]

@@ Baris 1.153: / Baris 1.153: @@
 <!--T:279-->
 {|
-|'''Study type'''| | '''Characteristics'''| | '''Advantages'''| | '''Disadvantages'''
+|'''Study type'''| '''Characteristics'''| '''Advantages'''| '''Disadvantages'''
 |-
-| Descriptive| | * Observational
+| Descriptive| * Observational<br />
-* Describe patterns of disease in the population | | * Relatively quick and easy
+* Describe patterns of disease in the population | * Relatively quick and easy<br />
 * Can generate hypotheses on possible risk factors for further investigation
-* Doesn't require random sampling or high degree of rigour | | * Doesn't support hypothesis testing or inference for possible risk factors
+* Doesn't require random sampling or high degree of rigour | * Doesn't support hypothesis testing or inference for possible risk factors <br />
 * Can't estimate prevalence or incidence or exposure proportions
 * Subject to inherent biases and errors because of the nature of the data
 |-
-| Cross-sectional| | * Observational
+| Cross-sectional| * Observational<br />
 * Observation at point in time
-* Outcome/exposure not considered in selection| | * Disease prevalence in exposed and unexposed populations can be estimated
+* Outcome/exposure not considered in selection| * Disease prevalence in exposed and unexposed populations can be estimated<br />
 * Exposure proportions can be estimated
 * Relatively quick and cost-effective
-* Can study multiple factors at once| | * Unsuited to investigating rare diseases
+* Can study multiple factors at once| * Unsuited to investigating rare diseases<br />
 * Less useful for acute diseases
 * May be difficult to control potential confounders
@@ Baris 1.176: / Baris 1.174: @@
 * May be problems with reliability of data/recall for historical data
 |-
-| Case-control| | * Observational
+| Case-control| * Observational<br />
 * Retrospective longitudinal
-* Selection based on outcome status| | * Good for rare diseases
+* Selection based on outcome status| * Good for rare diseases<br />
 * Relatively rapid and cost-effective
 * Relatively small sample sizes
 * Often use existing data
-* Can study multiple factors at once| | * May be difficult to establish causality
+* Can study multiple factors at once| * May be difficult to establish causality<br />
 * Can't estimate prevalence or incidence or exposure proportions
 * Rely on access to historical data or recall
@@ Baris 1.189: / Baris 1.187: @@
 * Selection of controls often difficult
 |-
-| Cohort || * Observational
+| Cohort |* Observational<br />
 * Prospective longitudinal
-* Selection based on exposure status| | * Can calculate incidence in exposed and unexposed individuals
+* Selection based on exposure status| * Can calculate incidence in exposed and unexposed individuals<br />
-* Can provide strong evidence for causality| | * Exposed/unexposed proportions cannot be estimated
+* Can provide strong evidence for causality| * Exposed/unexposed proportions cannot be estimated<br />
 * Large sample sizes, particularly for rare diseases
 * Can only investigate small number of potential risk factors at any one time
@@ Baris 1.200: / Baris 1.198: @@
 * May be difficult to control potential confounders
 |-
-| Field/clinical trials| | * Intervention
+| Field/clinical trials| * Intervention<br />
 * Longitudinal
-* Randomised selection| | * Relatively quick
+* Randomised selection| * Relatively quick<br />
 * Good for helping establish causation
 * Usually strong internal validity
 * Relatively small sample size and usually short duration
-* Can't estimate incidence/prevalence| | * May be problems with external validity, particularly to diverse target population
+* Can't estimate incidence/prevalence| * May be problems with external validity, particularly to diverse target population<br />
 * Can be expensive depending on the intervention and situation
 * Requires significant cooperation and rigorous management